Published semi-annually by theMARGINS Office

Lamont-Doherty Earth Observatoryof Columbia University

61 Route 9WPalisades, NY 10964 USA

The MARGINS SEIZE Initiative: Recent Progress and Future Directions

Julia Morgan1 and Elizabeth Screaton2, Nathan Bangs3,Susan Bilek4, and Demian Saffer5

1Rice University, 2University of Florida, 3University of Texas, 4New Mexico Tech, 5Pennsylvania University

The MARGINS SEIZE (the Seis-mogenic Zone Experiment) Initiative was developed to address fundamental questions concerning earthquake and tsunami generation in subduction zones (MARGINS Science Plan, 2004). Since first designed in 1997, this research initiative and related studies have sig-nificantly changed our understanding of seismogenic processes and controls along convergent margins. As with all of the four MARGINS Initiatives, two focus sites were identified in which the basic initiative questions could best be answered, here the Central America and Nankai, Japan convergent margins. Con-vergence at the Central America margin produces earthquakes that tend to be rela-tively small in magnitude (M~6.5-7.5) with limited slip distributions, whereas the Nankai Trough is characterized by regular, larger magnitude (M~8-8.5) earthquakes. Both locales have produced tsunamigenic earthquakes that pose sig-nificant risks to local communities. The two focus sites offer the potential to measure active processes relating to the earthquake cycle (e.g., seismicity,

deformation, and fluid flow), the ability to image and sample both the incoming sub-ducting plate and the deforming forearc region, and the possibility of drilling into the active fault zone. Both locales are also targets of active or proposed Integrated Ocean Drilling Program (IODP) drilling. The Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) has already begun, with three expeditions completed by the D/V Chikyu off the Kii Peninsula of Japan. Similar drilling projects are be-ing considered for Costa Rica off the Osa and Nicoya peninsulas, e.g., the Costa Rica Seismogenesis Project (CRISP), and at other seismogenic zones (e.g., Sumatra, and the Kanto region of Japan). The synergies among the MARGINS Program, IODP, and international collab-orations, have led to major advances in reaching the SEIZE science objectives. The questions that guide SEIZE re-lated research have been refined over the years, with significant community input, as our understanding of subduction thrust processes has evolved. The initial science questions included:

In This Issue:Science Article SEIZE Initiative ...................... 1-6From the MARGINS Chair ...... 7-8Steering Committee Meeting 9-10News From NSF ..........................10MARGINS Workshop Reports IBM 2007 ...........................12-15 RCL at AGU ..............................16Database Report .........................17MARGINS Future .......................18Publications ................................19Education and Outreach Postdoctoral Fellows ................20 MARGINS Student Prize .........21 MARGINS Lectures ............22-23 MARGINS Mini Lessons ..........302008 NSF Awards ................26-29MARGINS Office ........................29Contact Information ..................31

New

slet

ter #

20,

Spr

ing

2008

Figure 1. Seismicity recorded over the Nicoya Peninsula of Costa Rica by the CRSEIZE network (gray triangles). Scaled earthquakes plotted in red in map view (a) and cross-section (c) are a subset of the total low error catalog (open black circles) used in this study. Black saw-toothed curve represents the middle America Trench. Location is shown in (b). Modified from Ghosh et al. (2008).

-86.5°� -86.0°� -85.5°� -85.0°�

9.5°�

10.0°�

10.5°�

11.0°�ML=2, 3, 4

100

50

0

0° 50° 100° 150°

70 km

(a)

(b)

(c)

10°

-90° -80°

Page 2 MARGINS Newsletter No. 20, Spring 2008 SEIZE Report• What is the physical nature of asperitites? • What are the temporal relation-ships among stress, strain and pore fluid composition throughout the earthquake cycle? • What controls the updip and downdip limits of the seismogenic zone of subduction thrusts? • What is the nature of tsunami-genic earthquake zones? • What is the role of large thrust earthquakes in mass flux?

Scientific progress was evaluated and findings reviewed during the MARGINS SEIZE Theoretical & Experimental Institute in Snowbird, Utah in March 2003, and many new questions were posed [see Dixon and Moore, 2007, and papers therein]. For example, the hy-pothesis that clay dehydration reactions (i.e., smectite to illite) alone govern the updip limit of seismogenesis was refuted on the basis of laboratory friction studies showing that both clay phases are veloc-ity strengthening [Saffer and Marone, 2003]. However, secondary effects of diagenesis, including lithification, fabric development, and mineral dehydration, may come into play [J.C. Moore et al., 2007; Marone and Saffer, 2007; Saffer and Marone, 2003], as will the mineral-ogic inputs into the subduction zone [e.g., Underwood, 2007]. Such laboratory studies demonstrate the need to identify the complex physical, chemical, pore fluid, and mechanical interactions that must contribute to the onset and mode of stick-slip behavior [e.g., Moore and Saffer, 2001; Marone and Saffer, 2007], particularly under experimental condi-tions that more closely mimic those in situ [e.g., Moore and Lockner, 2007]. Another fundamental new obser-vation was that seismogenic faults, including subduction megathrusts, ac-commodate a much broader spectrum of slip modes and rates than previously imagined. Aseismic slip events and silent earthquakes, episodic tremor, and low-frequency earthquakes, all occur on the same faults known for “fast” earth-quakes [e.g., Dragert et al., 2001; Rog-

ers and Dragert, 2003; Ito and Obara, 2006], but appear to fall into a separate class of rupture [Ide et al., 2007]. These observations may relate to scaled hetero-geneities and differing modes of seismic energy radiation on the subduction thrust interface [e.g., Bilek, 2007; Richardson and Marone, 2008], leading to new questions to guide SEIZE research [e.g., Hyndman, 2007]:

• What controls the overall distribu-tion of seismic energy release dur-ing a subduciton zone earthquake? • What controls the sometimes het-erogeneous distribution of lock-ing patterns on the plate interface and subsequent variations of en-ergy release during earthquakes? • What controls the rate of prop-agation and slip rates of earth-quakes and the distribution of fast, slow, tsunamigenic, and silent earthquakes in time and space? • What is the nature of temporal changes in strain, fluid pressure and stress during the seismic cycle? • What are the prediction errors as-sociated with typical mechanical models?

In this update of the SEIZE initiative, we highlight recent successes in answer-ing these fundamental questions, particu-larly at the two focus sites. In addition, we review advances and findings in re-lated studies, including laboratory experi-ments, exhumed fault zones, and numeri-cal models. This brief summary is intend-ed to set the stage for the planned SEIZE meeting in September 2008 (p. 11). Central America

The Central American subduction margin is designated a focus site for both the Subduction Factory and SEIZE Initiatives of MARGINS, resulting in a convergence of scientific effort. Sci-entific progress has also benefited from strong international collaborations, in particular, with Nicaraguan, Costa Ri-can, and German research institutions. Recent results were reviewed during

the 2007 integrated SEIZE and Sub-duction Factory workshop in Heredia, Costa Rica [Silver et al., 2007]. Significantly, margin seismicity (i.e., earthquake magnitude and recur-rence) is highly segmented by along-strike variations in the incoming Cocos plate [e.g., Protti et al., 1995; Bilek et al., 2003; Bilek, 2007), and possibly the upper plate as well (Marshall et al., 2007]. The relatively smooth plate generated at the East Pacific Rise (EPR) subducts beneath Nicaragua, leading to earthquakes of variable size and source duration, including the 1992 tsunami earthquake. A rougher plate, including many seamounts generated along the Cocos-Nazca spreading center (CNS), subducts beneath Central Costa Rica, re-sulting in more frequent fast earthquakes up to M=7.0. Subduction of the Cocos Ridge under southern Costa Rica appears to produce M>7.0 events every ~40 years. The transition between the smooth EPR generated seafloor and rough CNS gen-erated seafloor is currently subducting beneath northern Costa Rica, offshore of the Nicoya Peninsula. This area is subject to large (M=7.7) fast earthquakes every ~50 years. The region is seismically quiet at present but showing significant elastic strain buildup for the next event, prompting intense scientific scrutiny. The Costa Rica Seismogenic Zone Experiment CRSEIZE project instru-mented the Costa Rica plate boundary with seismometers, GPS, and fluid flow meters to better resolve the nature of plate boundary deformation and seis-micity [e.g., Schwartz and De Shon, 2007; Norabuena et al., 2004]. The downdip extent of the seismogenic zone beneath the Nicoya Peninsula is well constrained by microseismicity to lie above the base of continental crust (~30 km depth, Figure 1) and the location of the 300° isotherm from thermal models [Harris and Wang, 2002; Schwartz and DeShon, 2007]. The updip limit of the seismogenic zone is not as well defined. The seaward extent of microseismicity maps to 15-17 km (Figure 1), is bounded by the modeled 200-250° isotherm, and

MARGINS Newsletter No. 20, Spring 2008 Page 3

is offset across the EPR-CNS boundary [DeShon et al., 2006]. In contrast, geo-detic studies constrain the locked zone to just offshore (Figure 2), with an updip limit coincident with the modeled 100-150° isotherm [Norabuena et al. 2004]. A more recent examination of frequency-magnitude relationships based on the complete CRSEIZE earthquake catalog shows a broad correlation with geodetic data (Figure 2), finding low b-values (or highest stress) in the geodetically locked patch of central Nicoya [Ghosh et al., 2008]. The transition between the locked and microseismic zones may reflect downdip fault zone weakening re-lated to pore pressures generated by low-grade metamorphic reactions [Schwartz and DeShon, 2007], but also raises the question as to how best to define the updip limit of the seismogenic zone. Silent slip events were first detected beneath Costa Rica through onshore GPS deployments, and are interpreted to originate immediately updip and down-dip of the currently locked shallow plate interface [Norabuena et al. 2004]. This differs from other settings in which silent slip events appear to originate downdip of the seismogenic zone on the hotter portion of the megathrust fault [e.g., Dragert et al., 2001]. However, in both settings, silent slip corresponds to a fric-tional transition between stable sliding and stick-slip behavior. Tremor has also been detected in Costa Rica with OBSs positioned near the toe of the accretionary prism [Brown et al., 2005]. Elsewhere, deep tremor has been attributed to fluid generated by dehydration processes deep in the slab [Obara, 2002], and the same may be true in this shallower setting [Schwartz and De Shon, 2007]. A dense network of continuous GPS, seismic, and tilt stations has now been installed across the Nicoya Peninsula in collaboration with GEOMAR researchers, to improve the understanding of slow slip along this plate boundary [Psencik et al., 2007]. Interestingly, a strong correlation has been observed between shallow tremor and fluid flow transients measured at flowmeters collocated with the OBSs.

This correlation is modeled as a po-roelastic response to loading by slow slip along the plate interface near the up-dip limit of the seismogenic zone [Brown et al., 2005]. Elsewhere, pressure changes observed at subseafloor observatories near the trench have been correlated with very low frequency (VLF) earthquakes [Davis et al., 2006]. Strong linkages among stress, strain, and fluid flow over large distances have been demonstrated by poroelastic models of forearc defor-mation in response to seismic activity [Cutillo et al., 2006]. Other numerical modeling studies relate variations in the location of the updip limit of seismicity with cooling of the subducting plate by fluid flow, including along-strike flow [Spinelli and Saffer, 2004, 2007]. Questions remain about the cause of tsunami earthquakes offshore of Ni-caragua. New deep-penetration seismic data collected across the forearc and downgoing plate show fault grabens and isolated seamounts on the subducting plate, and complex forearc structure, all of which may play a role in earthquake rupture mode in this setting [McIntosh

et al., 2007]. Uniquely, the Nicaraguan seismogenic zone is centered on a base-ment high, in contrast with Wells (2003) observation that most seismogenic zones correlate with forearc basins. Although recent studies of the Cen-tral America subduction margin have revealed substantial detail about seis-mogenic zone processes and properties, many critical gaps remain. In particular, a unique opportunity exists to capture the next earthquake along Nicoya, and to further clarify the connections among stress, strain, the range of fault slip be-haviors, and the roles of rock properties and fluid processes. This will require new deployments of geodetic and seismic net-works, both onshore and off, to provide spatially dense, long-term geodetic and seismic measurements. This is a clear target for future MARGINS and IODP cooperation, particularly with the strong data bases already existing with the in-terseismic period.

Nankai Trough

Major milestones for the Nankai Trough focus site include the commercial

Figure 2. Geodetically determined locking of the Costa Rican plate boundary (white contours, dashed where poorly constrained) from Norabuena et al. (2004) with variations in b-value, and interplate seismicity (dark circles). High resolution bathymetry shows the subducting Fisher seamount chain, coincident with undulations in locking and high b-values. Inset shows a comparison of b-values and percent locking; the negative correlation suggests that b varies inversely with locking. (Modified From Ghosh et al., 2008).

0.81.01.21.41.61.82.0

0

50

km

N

30

40 50

60

30

20

20

30

Fishe

r sea

mount

85 m

m/yr

EPR CNS

b−value

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

0 20 40 60 80Locking (%)

b−va

lue

Corr=−0.53

Page 4 MARGINS Newsletter No. 20, Spring 2008

(VLF) thrust earthquakes [Ito and Obara, 2006]. These observatories will measure pore pressure, temperature, strain, tilt, and seismicity to test hypotheses con-cerning strain localization, fault locking, and fluid pressurization along the fault. The first riser drilling in IODP will tar-get the major splay fault implicated in co-seismic slip and tsunami generation (~3 km below seafloor), and ultimately, deeper portions of the splay fault and the co-seismic portion of plate bound-ary fault (~6 km below sea floor) for sampling and observatory installation. Analysis of previously acquired 3-D seismic data along the Nankai Muroto transect has yielded information about the frontal portion of the accretionary prism, the subduction thrust, and underthrust strata across the updip seismic-aseis-mic transition. Porosities and effective stresses inferred from velocity data sug-gest that the underthrust sediments and overlying decollement zone are nearly undrained during 20 km of subduction [Tobin et al., 2005]. These observa-tions are consistent with compaction disequilibrium inferred from porosities at boreholes within and seaward of the toe of the accretionary prism [Screaton

Figure 3. Representative 3D data volume showing relationships between in-sequence thrusts (light gray lines) and out-of-sequence branches of the splay fault (black lines) of the frontal accretionary prism. Note the truncation of a folded imbricate thrust sheet by the younger megasplay fault. See also G.F. Moore et al. (2007).

SEIZE Reportacquisition and processing of a 3D seis-mic volume offshore of Kii Peninsula, the chosen location for IODP seismo-genic zone drilling, and also comple-tion of the first three NanTroSEIZE IODP expeditions. Additionally, work is continuing on previously acquired seismic data and drill cores to better characterize the structure and properties of the plate boundary elsewhere. The 3D seismic surveys provide improved constraints on fault geometries and prop-erties for seismogenic zone drilling. The offshore Kii seismic volume has yielded detailed imaging of the megasplay fault system that rises steeply from the decollement zone to the seafloor [Figure 3; G.F. Moore et al., 2007].Evidence of recent large-scale slump-ing indicates that this out-of-sequence thrust system is active; structural and stratigraphic cross-cutting relationships also suggest a landward-breaking fault sequence consistent with co-seismic out-of-sequence thrusting [G.F. Moore et al., 2007]. Similar out-of-sequence thrusts have been identified at many other sub-duction zones, including Alaska, Sunda, and Columbia [G.F. Moore et al., 2007]. The geometry of such systems increases the likelihood of significant perturbations of the seafloor during slip, potentially leading to devastating tsunamis. The primary objectives of NanTro-SEIZE drilling are to sample and ob-serve within and surrounding the active seismogenic zone to obtain important ground-truth about the evolution of materials as they approach seismogenic depths [Tobin and Kinoshita, 2006; http://www.iodp.org/NanTroSEIZE]. The first three NanTroSEIZE expeditions (Expeditions 314, 315, and 316, all non-riser) are now complete, establishing the groundwork for future deeper drilling and planned observatories. Accomplishments include a 1400 m deep borehole drilled through the Kumano forearc basin and underlying accreted rocks, the deepest borehole ever drilled into an accretion-ary prism [Kinoshita, Tobin, Mo, and the Expedition 314 Scientists, 2008]. Coring of the Kumano basin, uplifted

above the megasplay fault, provides a unique record of the deformation history of this portion of the prism. Borehole breakouts confirm a transition from a vertical maximum compressive stress in the Kumano Basin to a horizontal maximum compressive stress seaward of the basin, suggesting a stress bound-ary across the splay fault. Recovery of shallow portions of the megasplay fault provide the first look at fault properties and composition. Analyses of slope cover and slope basin sediments offer the potential to identify mass movements in-duced by slip along the megasplay fault. Cores from the frontal thrust fault and its hanging wall suggest that this fault was active as the plate boundary fault for an extended period, in contrast to other margins where prisms systematically build seaward by imbricate thrusting. Future NanTroSEIZE activities will include sampling “subduction inputs” seaward of the deformation front to characterize the incoming materials and their properties. Additionally, two bore-hole observatories will be installed: one in the splay fault at a depth of ~400 m, and another immediately above the slip zone of the 1944 Tonankai M 8.2 earth-quake and recent Very Low Frequency

MARGINS Newsletter No. 20, Spring 2008 Page 5

et al., 2002], and allow for low effective stresses up to tens of km from the trench, possibly suppressing stick-slip behavior in this region [Scholz, 1998; Tobin et al, 2005]. Laboratory consolidation stud-ies of these underthrust sediments yield conflicting interpretations for the cause of the high porosities, which might reflect overpressures within low permeabil-ity underthrust sediments [Saffer, 2003, 2007; Gamage and Screaton, 2006] or diagenetic hardening that prevents dewatering [Morgan et al., 2007]. Inde-pendent of the cause of these anomalous underthrust porosities, downdip changes in consolidation and pore pressures may influence decollement downcutting and transitions in mechanical proper-ties near the updip limit of the seismo-genic zone, consistent with decreasing reflection amplitudes of the decolle-ment horizon [Bangs et al., 2004]. Mineralogic analyses of older drill cores from the Muroto and Ashizuri transects across the Nankai Trough provide the basis for new thermal and geochemical modeling to track the pro-gression of diagenetic reactions within the accreting and subducting sediments [Spinelli and Underwood, 2005; Spinelli et al., 2007]. These studies clarify the mechanisms responsible for pore volume loss and associated strength changes during accretion that may influence the stress conditions along the margin. In addition to IODP borehole-based studies, seafloor and on-land observa-tions continue to provide important context for borehole observatory data. Ongoing efforts by Japanese institutions include ocean bottom seismometer arrays and heat flow studies; related MARGINS investigations will measure fluid flow at seeps in the Nankai Trough. In addi-tion, laboratory studies that characterize mechanical and hydrologic properties of both borehole samples and exhumed fault rocks from the seismogenic zone are crucial for attaining SEIZE objectives. Modeling studies [e.g., Ge and Screaton, 2005; Screaton and Ge, 2007] provide in-sight to predicted fluid pressure changes during fault slip, and will help guide

selection of future observatory sites. Related Studies

Events and resulting studies at non-MARGINS sites also have added substantially to our growing understand-ing of seismogenic zone processes at convergent margins. Most notable was the devastating 2004 Sumatra-Andaman earthquake and tsunami. This margin offers the potential to study immediate post-seismic processes and structures to compare with those being documented at different stages of the seismic cycle else-where. The Cascadia margin is of great interest as the only active convergent mar-gin along the continental United States, and one that provides direct linkages to other NSF programs such as EarthScope. Observations of slow plate boundary slip demonstrate that the megathrust fault is currently active downdip of the inferred seismogenic zone [e.g., Dragert et al., 2001]. In addition, two clusters of low-magnitude thrust earthquakes have been identified within the nominally “locked” or “transitional” part of the megathrust, updip of where episodic tremor and slip have been documented [Trehu et al., 2007]. Paleoseismic studies carried out through correlation of basin turbidites have extended the record of large mega-thrust earthquakes back to the Holocene, providing improved constraints on their extents and frequencies [e.g., Goldfinger et al., 2003]. Globally, as monitoring of subduction zones has increased, so have the observations of slow slip events in many different settings, raising further questions as to their genesis [Schwartz and Rokoksy, 2007]. These kinds of stud-ies of active margins will continue, and augment MARGINS investigations. Studies of exhumed accretionary complexes provide additional insights to seismogenic processes. Field studies of pseudotachylites in the Kodiak accretion-ary complex provide evidence for fric-tional melting induced by seismogenic slip, accompanied by diapiric intrusions indicative of pressurized fluids [Rowe et al, 2005]. Additionally, carbonate

cementation, pressure solution features, and quartz veining and cementation with increasing temperatures are recorded in accretionary prism sediments and may be key factors controlling the updip limit of the seismogenic zone [J.C. Moore et al., 2007]. Such reactions would strengthen the upper plate, allowing it to store energy for an earthquake; furthermore, quartz ce-ments or veining may facilitate velocity-weakening behavior within fault zones. Future of SEIZE

Despite great advances in our under-standing of seismogenic zone processes, many fundamental questions still re-main. Fortunately, the SEIZE initiative is entering an extremely active phase, particularly as results of field studies, seismic surveys, and drilling yield data and samples for laboratory examination and model testing. Ongoing studies are documenting fluid flow at seeps in the Nankai Trough and deformation and seis-micity on the Nicoya Peninsula. Future measurements in IODP boreholes will provide additional data on the relation-ship between deformation, fluid pres-sures, and fluid flow. New observations of seafloor deformation and seismicity will increase our understanding of slow slip events, and their relationships to fluid flow processes. Other key data sets and studies that will help to achieve SEIZE objectives, particularly along the Central American margin, include combined active and passive source seismic tomo-graphic studies to better constrain the physical properties of the upper and lower plates for relocating earthquakes, and for modeling forearc deformation and fault behavior. At both Central America and the Nankai margins, observatories will be necessary to understand changes through time. These in-situ measurement pro-grams face long time frames for success, and are a clear direction to move during the next generation of MARGINS. Laboratory experimental studies and theoretical modeling efforts are criti-cally needed to investigate processes that

Page 6 MARGINS Newsletter No. 20, Spring 2008

control the mechanical, frictional, and hydrologic behavior of fault and wall rocks over realistic ranges of pressure, temperature, composition, and time. Laboratory and field data also need to be integrated through modeling studies to rigorously tie observations to geophysi-cal processes. In particular, modeling can help improve our understanding of fluid pressure and hydration state of faults, and the interaction among upper and lower plate deformation and fluid processes throughout the seismic cycle. These modeling efforts require advanced numerical capabilities and interdisciplin-ary collaborations to incorporate more realistic constitutive relationships and

SEIZE Reportto integrate deformation, heat and geo-chemical transport, and fluid flow. The upcoming SEIZE meeting, planned for September 2008, will further evaluate the progress towards achieving the SEIZE objectives, inspire new ap-proaches for reaching these objectives, and identify new questions based on recent discoveries. An important issue for consideration at the September 2008 meeting will be how best to general-ize results from the SEIZE focus sites to other settings, and whether expan-sion of MARGINS related studies to new locales might better answer some of the persistent scientific questions.

References

Bangs, N.L., Shipley, T.H., Gulick, S.P.S., Moore, G.F., Kuromoto, S., Nakamura, Y., 2004, Evolution of the Nankai Trough decollement from the trench into the seismogenic zone: Inferences from three-dimensional seismic reflection imaging, Geology, 32, 273-276.

Bilek, S. L., Schwartz, S.Y., and DeShon, H. R., 2003, Control of seafloor roughness on earthquake rupture behavior, Geology, 31, 455 – 458.

(Continued on pg 24)

The MARGINS Office (MO) and Steering Committee aim to support efforts that expedite synthesis of results from MAR-GINS science in the various focus areas and initiatives. To this end, MO offers to help MARGINS-funded investigators organize and fund Mini-workshops held at national meetings for the purpose of bringing together a group of multi-discipli-nary investigators to synthesize results to date. Such Mini-workshops can be associated with GSA, AGU, or other national meetings at which your research area is well represented. Shorter workshops (2-4 hours) tend to be more successful due to competing time requirements. They can bring together multiple investigators from a single focus site or from both focus sites within an initiative, or can address a theme that transcends initiatives, according to what makes the most scientific sense and where there is the greatest need.If you are interested in hosting a Mini-workshop, coordinate with your colleagues, and then send the MARGINS Office a 1-2 page outline of your meeting plan as soon as possible (margins@nsf-margins.org). Requests should generally come not later than 3 months ahead of the meeting. The MARGINS Steering Committee (MSC) will first review the submitted Mini-workshop proposal, which will be later reviewed and supported by the MARGINS Office. Your write-up should include:

Scientific rationale for the meeting and reasons for its timeliness.• Evidence that a wide group of interdisciplinary researchers would be able to attend.• A draft scientific program for the Mini-workshop.• The national meeting with which the Mini-workshop would be associated.• The format desired (evening, half-day or full day, pre- or post-meeting) and acceptable dates.• Size of meeting envisioned.• Anticipated cost items (meeting space, refreshments, A/V equipment, etc.). Note that a detailed budget for these costs • is not initially required, and travel or lodging costs for participants cannot not be provided.

There are some ground rules intended to maximize the benefit of such workshops to a larger scientific community and emphasize opportunities for interdisciplinary integration. A number of arrangements will be made upon approval of a Mini-workshop proposal: MO will meet the cost of a meeting room, presentation equipment and non-alcoholic refresh-ments, and will assist the meeting conveners in the logistical arrangements. Conveners are responsible for developing the science program and communicating with workshop participants on scientific matters. Any MO-supported Mini-work-shop will be open to all interested parties and will be advertised via the MARGINS mailing list and website. Workshop conveners will provide a brief write-up of the major results of the meeting for dissemination via the MARGINS website and newsletter. The MARGINS Office and Steering Committee (Visit www.nsf-margins.org/miniworkshops.html for more information)

Call for Interdisciplinary MARGINS Mini-workshop Proposals

MARGINS Newsletter No. 20, Spring 2008 Page 7

From the MARGINS Chair - Spring, 2008Geoff Abers, Lamont-Doherty Earth Observatory of Columbia University

E-mail: abers@ldeo.columbia.edu

From the Chair

As you are aware, the MARGINS Of-fice has made another, unexpected move. After several productive, fruitful years at Boston University, I moved to Lamont-Doherty in January of 2008. Part of the challenge is taking the MARGINS Of-fice along. The BU staffers were unable to make the move, but I am especially grateful to Cary Kandel for sticking with the BU office to its end – Cary is on her way to Colorado for graduate school, but has been a huge help through the transition. Fortunately an excellent new group has been assembled to restaff the Office (see p. 29). Niva Ranjeet is the new full-time Coordinator, and is quickly and enthusiastically learning the ropes. She is responsible for day-to-day Office operations. Kathryn Kennedy has taken most of the administrative duties part time as well as her prior Lamont duties, and has made it possible to restart regu-lar work very smoothly. I am also very fortunate to secure Andrew Goodwillie as a senior scientific coordinator; many of you know Andrew from his day job with the Marine Geoscience Data Sys-tem. He is helping with education, data, and senior-leadership projects associated with the Renewal.

Through the move we have contin-ued to operate the various meetings, speaker tours, AGU events, web pages and educational projects. Most of the major ones are described elsewhere in this issue. November saw a very suc-cessful joint MARGINS/IFREE (Japan) workshop on the Izu-Bonin-Mariana focus site, which demonstrated to me the tremendous value of joint interna-tional ventures, with some very exciting results coming out of focused programs in two countries. I was impressed by the level of sophistication through which geophysicists, geochemists and marine geologists were able to analyze each other’s work – this kind of natural inte-gration through cross-education is one

of the real successes of the MARGINS approach. Other recent events include a very well-attended reception and student forum at AGU at which many Student Prize participants displayed and discussed their presentations. Thanks to the Boston University Department of Earth Sciences for partial support of this event. Finally, the MARGINS Mini-Les-sons program continues to make progress through recent workshops at GSA, AGU and Ocean Sciences, in garnering new undergraduate course modules based on various aspects of MARGINS research (see highlight on p. 30).

The MARGINS community contin-ues to get new science done. Papers are starting to appear in the Central America Special Theme of G-Cubed, related to last year’s meeting, and the Papuan Contin-uum special issue of JGR-Earth Surface just published over 20 S2S-related pa-pers. R/V Marcus Langseth is underway and collecting data while I write this, in the Central America focus site; we are pleased that the first expedition of this major seagoing facility is a MARGINS one. Early data from shipboard and onland PI’s (Holbrook, Lizarralde, van Avendonk, et al.) looks great, promising impressive things to come. Also, drilling continues at the NanTroSeize focus site, and we await first results to be presented at a SEIZE thematic workshop scheduled for September.

Upcoming Review Over the last few months, the MAR-

GINS Steering Committee (MSC) and Office has been gearing up for the decadal review, scheduled within the next year. Last November the MSC sent an important Open Letter to the community regarding the review process, which I urge you to read (see p.18, and www.nsf-margins.org). We emphasize that the current program is still accepting

proposals within the current framework so ample opportunity should exist for new science; proposals for integration and synthesis activities are particularly encouraged by the MSC. Beyond that, there is much interest in formulating a successor program – a successor is by no means guaranteed, and it will take some vision and excitement to bring it about, but efforts are underway. We have opened up a web-based forum where we encourage groups to post white papers or other idea pieces (see Box, p. 8). Planning discussions now occur within all large meetings that MARGINS sponsors. Some groups have organized initiative-specific working groups that have met to develop potential goals for future programs; an S2S working group met in early March, and an RCL working group met in early April. Anybody interested in organizing similar events should approach me and/or other Steering Committee members. The goal behind the white papers, working groups, and small discussions is to gener-ate ideas in advance of the review; these ideas are drafted as short highlights of promising future directions to assist the review panel in its deliberations. This approach maximizes the input into the re-view as efficiently as possible, by rapidly generating cogent, written documents. If a new program succeeds, as we hope, then one of the first orders of business will be to initiate community-based, open workshops designed to generate new sci-ence plans.

The Steering Committee is working with NSF to finalize a timetable for the review. It is likely that a review com-mittee will be constituted and charged in Fall 2008, at which time the MSC will deliver review materials to NSF, with an early 2009 meeting of the review. The review committee is likely to be run at the Geoscience Directorate level, given that both Ocean and Earth Sciences in MARGINS participate (see Letter, p. 10).

Page 8 MARGINS Newsletter No. 20, Spring 2008

In the mean time, the Steering Committee and Office will be hard at work preparing summaries and syntheses of each part of the program, evaluations and records of major events and accomplishments, and will be encapsulating the various ideas of how the future should go.

Here is where you come in. Around

the time you receive this, if not earlier, we will be soliciting research “Nuggets” from present and former MARGINS PI’s and related scientists. These Nuggets should be short, 1-paragraph summaries of key research results or plans, along with hopefully-compelling graphics. Nuggets were solicited for the Midterm Review in 2004 with much effect; they present a compelling picture of the sci-ence being done in the program, and

make it much easier to show what the program is capable (see review.nsf-margins.org). Please, when the request comes, take some time to respond – it is a great opportunity to showcase your best science.

Changes

This Spring I have had the pleasant task of inviting three new members to join the Steering Committee, following MSC recommendations. Susan Bilek is an earthquake seismologist who has made important contributions to understanding the earthquake source in subduction zones, and has been active in the Central America SEIZE site. Tom Dunne is a pioneer in quantitative analysis of land-form development, and brings a broad

perspective to S2S planning. Mark Behn is a geodynamicist with broad interests, and has been developing models of how magmatism relates to extension as well as flow beneath volcanic arcs. Welcome Susan, Tom and Mark. Sadly, with each new group I must also say goodbye to members who I have worked with for several years; thanks immensely to Don Reed, Juli Morgan, Peter van Keken and Paul Umhoefer for all your hard work. This group that has been rotating off the last year has been instrumental in bringing this first decade of MARGINS to fruition, leaving the current members in a good position to steer through the Review process.

-G. Abers, April 10, 2008

On-Line Discussion Forum: Future of MARGINS

The MARGINS Office has set up a moderated open forum on its web page for community-wide, engaging discussions about issues relevant to the future of the MARGINS program.

MARGINS will undergo its decadal review in early 2009, and, in preparation, the Steering Committee seeks input from the community on directions for a potential successor program. Please see the Steering Committee Open Letter of November 2007, available on the forum and on page 18 of this newsletter.

We are particularly interested in thoughtful, creative position pieces emerging from groups interested in the program’s future directions.

Go to www.nsf-margins.org/forum and take up the discussion!

Here are just some of the discussion topics on the MARGINS forum:

• Subduction Studies Should Continue: Top Nine List• Stern-Klemperer: U.S. Passive Margins: Are We Missing an Important Opportunity?• MARGINS-EarthScope collaborations• Open letter from MARGINS STCOMM on MARGINS future

Anyone can view the forum postings. To respond to a posting or to create a new topic for discussion, simply click the REGISTER tab in the upper left. Once logged in, go to the MARGINS Discussion Board. To re-spond to a current posting or to start a new discussion select the REPLY or NEW TOPIC tabs on the upper right.

For more information about the forum, contact the MARGINS Office at margins@nsf-margins.org

MARGINS Newsletter No. 20, Spring 2008 Page 9

MARGINS Steering Committee Highlights, Fall 2007The MARGINS Steering Committee (MSC) met, with visitors, November 5- 6, 2007 at Hotel Halekulani, Honolulu, HI.1. Geoff Abers, MARGINS Chairman,

welcomed new committee members Na-than Bangs (UTIG) and John Swenson (UMinn-Duluth) and explained that the MARGINS Office would move from Boston University to Lamont-Doherty Earth Observatory (LDEO) in January 2008. The MARGINS web page would be supported by the Marine Geoscience Data System (MGDS) at LDEO.

2. Brian Midson, Assistant Program Direc-tor in NSF-Ocean Sciences, welcomed MSC and provided updates on MAR-GINS-related topics:

• Debbie Smith (WHOI) rotated to NSF as Program Director for the Ocean Drill-ing Program, including MARGINS responsibilities.

• The 2008 MARGINS budget will remain relatively flat at about $5.4M, not counting co-funding of some projects. This year sees the first co-funding with EarthScope, Tectonics.

• The MARGINS panel had considered 22 projects for funding, some were writ-ten after participation at MARGINS-sponsored workshops.

• The Community Surface Dynamics Modeling System (CSDMS) is jointly funded for five years by NSF-OCE and NSF-EAR.

• The MARGINS post-doctoral fellow-ship program is under-used. More applicants should apply.

• “Transformational” research will be considered as part of a proposal’s In-tellectual Merit criterion from January 2008.

• A recent GAO report highlighted data sharing policies.

3. Workshops• The successful MARGINS-sponsored

June 2007 SEIZE/SubFac initiative workshop held in Costa Rica attracted 140 participants. A G-Cubed Special Theme was opened (See p. 19). Sci-entific progress made at the Central America Focus Site highlighted the benefit of international collaboration (see Report in Fall 2007 Newsletter).

• Juli Morgan summarized the August 2007 IODP-sponsored Geohazards workshop (see Report in Fall 2007 Newsletter) which attracted almost 90 attendees. The importance of emphasizing geohazards in proposals was recognized. Potential connec-tions between MARGINS initiatives and IODP geohazards projects were discussed, including links within the S2S initiative between submarine landslides and tsunamis. Report avail-able in Fall 2007 Newsletter.

• Paul Umhoefer presented highlights of the March 2007 MARGINS-EarthScope workshop (see Report in Spring 2007 Newsletter). More than 70 researchers attended. Compari-sons between the Gulf of California MARGINS Focus Site and the Walker Lane/Salton Trough area, which is to be studied under EarthScope, en-ergized the workshop. Collaborative cross-disciplinary projects within MARGINS, EarthScope and the NSF Continental Dynamics program had been encouraged. Potential links with EarthScope for Cascadia region stud-ies were discussed.

• MSC members discussed the upcoming MARGINS-IFREE IBM Subduc-tion Factory workshop (Nov 2007, Honolulu), with the hope that active discussion would highlight the future of a SubFac-like initiative within a next-generation MARGINS program. (see Report, p. 12-15).

4. Data Management• Andrew Goodwillie of MGDS (www.

marine-geo.org/margins) summa-rized the status of the MARGINS database, including the creation of entries for land-based field programs, the on-going development of database tools, updates to GeoMapApp (www.geomapapp.org), and results from a workshop focused on international data exchange (see Report in Fall 2007 Newsletter). The high-quality bathymetric and magnetic grids off Central America contributed to the MARGINS database by Weinrebe and Barckhausen were welcomed as examples of international data shar-ing.

• Kerstin Lehnert of LDEO’s Geoinfor-

matics for Geochemistry group (www .geoinfogeochem.org) summarized the status of EarthChem, which pro-vides portals to the PetDB, NAVDAT and GEOROC databases and of the SESAR registry (www.geosamples.org) for assigning unique identifiers to samples. Examples from the new SedDB (www.seddb.org) sedimentary geochemistry database were shown.

• Ramon Arrowsmith of Arizona State University presented an overview on the GEON (www.geogrid.org) cyber-infrastructure project. He demonstrat-ed some of its tools and capabilities for data ingestion and visualization.

5. Initiative Updates• Juli Morgan and Nathan Bangs provided

an update of the SEIZE initiative, including recent findings at the Costa Rica and Nicaraguan sites, and the status of drilling at the NanTroSEIZE site (See Initiative Review on p. 1).

• Paul Umhoefer updated the committee on the RCL initiative. Activity at the Gulf of California site has attracted more researchers which has enriched the scope of scientific questions being asked. Many papers are appearing. (see Initiative Review on p. 16).

6. Education and Public Outreach• Jeff Ryan reviewed the MARGINS mini-

lessons workshop (April 2007, report in Fall 2007 Newsletter). About 15 Mini-Lessons focused upon MAR-GINS-related data had been created (serc.carleton.edu/margins/overview.html). Similar mini-lessons workshops were held at the March 2008 Ocean Sciences meeting and are planned for the September 2008 SEIZE workshop, (update, p.30).

• The role of the Margins Education Ad-visory Committee (MEAC) and of a potential MARGINS REU program was reviewed.

• To increase the number of opportunities for schools to host a MARGINS Dis-tinguished Lecture Program speaker, last year’s DLP speakers have been retained, in addition to four new speakers. As a result, for the 2007-2008 session, DLP talks are scheduled for 35 of the 70 schools that applied. Digital audio-visual recording of pre-

Steering Committee

Page 10 MARGINS Newsletter No. 20, Spring 2008

sentations are encouraged.• Summariesweregivenfortheupcoming

Fall 2007AGUmeeting events, in-cludingtheRCLworkshop(convenersBuck/Umhoefer),aMini-workshoponDataResources, theMSCluncheon,MARGINS reception and studentpostersession,andeducation-relatedsessions of interest toMARGINSresearchers.

7.SteveHolbrook,ChairmanoftheMarcusLangsethScienceOversightCommittee,summarizedthecertificationprogressforthenewmulti-channelseismicplatformR/VMarcusG.Langseth.Thefirstfullscience cruise is expected to sail inFebruary2008.

8.MARGINSpublications Abers reviewed the effort andcost in-

volvedwithgeneratingbookscompared

withthejournalspecialissuemodel,asusedforrecentmeetings.Factorsinclud-ing speed of publication, accessibilitytopapers,andimpactofcitationswereconsidered.

9.MARGINSDecadalReviewThereviewoftheMARGINSprogramwilltakeplacearound2009.AberslistedtopicsfromtheSpringMSCmeetingthatmustbeaddressedforthe2009decadalreview:demonstratemajorsuccesses–summarizewhatweknownowthatwedidnotknowadecadeago;identifysig-nificantnewsciencequestions;developacommunity-supportedapproachforthereview.NewissuestobetackledbyMSCinclude:howtoidentifygapsincurrentinitiatives;howtoencouragesynthesisbetweeninitiatives;decidewhichmajormeetingsneedtohappen.Additionally,

potentialdirectionsforasuccessorpro-gramshouldbeaddressed.

10.MARGINSsuccessorprogram Thecommitteediscussedideassurround-

ingasuccessorprogramtoMARGINS.Aproposalforsuchaprogrammustbeclear in addressingwhy a follow-onprogramisneeded.Usingasynthesizing,cross-disciplinaryapproach,incorporat-ingissuesofsocietalimpact(hazards),anddemonstratingtransformativethink-ing should form the core of a newprogram.Theissueofcenteringanewprogramaroundfocussites–thecurrentmodel–oraroundscientificthemeswillneedtobetackled.Justificationforanysuccessormustclearlyshowwhycorefundingcannotachievethesamegoals.

-Edited by Andrew Goodwillie

As youmay know researchersinterestedinvariousinitiativesoftheMARGINSProgramhavebeenmeet-inginmini-workshopstoreviewpastaccomplishmentsanddiscussfutureplansinordertopreparefortheup-comingdecadalreviewoftheentireProgram.Thismilestone review iscurrently planned for early 2009.Thereviewpanelwillbeconstitutedfrom amongst the active scientistsfromthebroaderGeosciencescom-munity,whoarenotcurrentlyreceiv-ingMARGINSProgramfundingbutareknowledgeableaboutitsvariousinitiatives.Thepanelwill report itsfindings and recommendations di-rectlytoNSF’sAssociateDirectorforGeosciences.

Thereviewpanelwillbechargedtonotonlyevaluatetheaccomplish-mentsoftheMARGINSProgram(ofwhichtherearemany)andthedegreetowhich different initiatives havefulfilled theobjectives stated in thecurrentSciencePlans,butwill alsolookatthecommunity’splansforthe

futureineacharea.Someoftheinitia-tiveshavehadachallengingtimeintheiroperationsduetovariouslogisti-calreasonsoverwhichwehadlittlecontrol.Thus,thepanelmayevaluatetheplans for the future to ascertainthatinadditiontobeingscientificallycompelling,thestudiesproposedarelogistically doable.Continuation oftheMARGINSProgramand futurefunding of various initiativeswilldependonthecommunitymakingastrongcaseforfundinginthecurrentmode, i.e., that tomake significantprogress inmargins-related science(andtoadvancesignificantobjectivesthatcannotbeachievedthroughcoremarine geosciences funding) it isnecessary to continue the Programbeyond the first decade.Thus, theseriousness and overall importanceoftheplannedreview!

Someofyoumayalsobeawarethat seismicR/VMarcusLangsethis finally fully operational and hasrecentlycompleteditsfirstscientificcruise investigating aMARGINS

projectfundedundertheSubductionFactoryinitiativeattheCentralAmer-icasfocussite.Thismulti-institution-alcruisewasapartofanamphibiousfieldprogram,withonshoreseismicrefraction study undertaken earlierandthemarinecomponentcompletedrecently.Thismulti-disciplinarystudyhadseveralimportantvolcanic,pet-rologicalandgeophysicalobjectivesandthehigh-resolutionfielddatacol-lectedbythe8-kmLangsethstreamerhas been described by the PI vari-ouslyas“beautiful”,“surprising”and“unusual” (http://faculty.gg.uwyo.edu/holbrook/Costa/MGL0804.html canbeconsultedforseismicimagesandfurtherexclamations).Ifthisisasampleofthequalityofdatawecanexpect from the community’sMCSflagship,thenR/VLangsethisafacil-itythatshouldserveourcommunitywellinfuture. BilalHaqForMARGINSProgramDivisionofOceanSciences

News From NSF

News from NSF: Decadal Review of MARGINS ProgramBilal Haq, National Science Foundation

MARGINS Newsletter No. 20, Spring 2008 Page 11SEIZE Workshop

NSF-MARGINS Workshop

The Next Decade of the Seismogenic Zone Experiment

Mount Hood, Oregon, September 22-26, 2008 Conveners: Nathan Bangs (nathan@utig.ig.utexas.edu), Don Reed (dreed@geosun.sjsu.edu), Demian Saffer (dsaffer@geosc.psu.edu), and Susan Schwartz (susan@pmc.ucsc.edu)

Applications Due: June 1, 2008

The NSF - MARGINS Seismogenic Zone Experiment (SEIZE) will hold a workshop Septem-ber 22 – 26, 2008 for approximately 80 scientists at Timberline Lodge on Mt Hood, Oregon. SEIZE seeks to understand and directly sample the seismogenic thrust zone at convergent plate boundaries. At the workshop, we will review the recent accomplishments and the current status of the SEIZE program, and define new directions for future work. The workshop will include invited speakers to present reviews of recent SEIZE projects, especially the Nankai deep drilling program and related studies at the NanTroSEIZE focus site, recent work on the Costa Rica focus site, other recent efforts from related programs, and related educational and outreach activities. The workshop will also focus on new directions, facilities, tools and strategies as well as possible new focus sites for potential suc-cessor programs. There will also be short oral and poster presentations. Throughout the workshop we will hold discussions to assimilate the recent accomplishments and evaluate what is needed to make the next steps in understanding seismogenic processes within the SEIZE program.

Participants chosen from applicants to this announcement will be provided with full or partial funding of their costs of travel, accommodation and meals. We encourage applications from those interested in this scientific endeavor, including those from outside the USA, and especially encourage applications from young investigators and under-represented groups. Present or previous MARGINS funding is not a prerequisite for attendance. Applicants should prepare a brief (no more than two pages) CV, and a brief (half-page) statement of why they are interested in participating in the meeting, and an abstract of what they hope to contribute to it. Detailed instructions are included on the web application form. Applications can be found online at: www.nsf-margins.org/SEIZE/2008 .

Applications close on June 1, 2008. Inquiries should be directed to the conveners (e-mail above).

Applications can be submitted online at: www.nsf-margins.org/SEIZE/2008

Page 12 MARGINS Newsletter No. 20, Spring 2008

Report of 2007 MARGINS-IFREE Workshop on the Izu-Bonin- Mariana Subduction Factory, Honolulu HI, November 7-11

Robert Stern (University of Texas, Dallas) & Douglas Wiens (Washington University in St. Louis)

Introduction

A 3.5-day workshop to discuss prog-ress and prospects for MARGINS Sub-duction Factory studies, IODP scientific drilling, and related studies of the Izu-Bonin-Mariana (IBM) subduction system was held at the Waikiki Beach Marriott in Honolulu, Hawaii on November 7-10, 2007. The IBM arc system extends al-most 3000 km from Japan to the south of Guam. It is one of two focus sites for NSF MARGINS Subduction Factory studies (the other being Central America), which investigates the transport and processing of material through subduction zones. The IBM system represents an “intra-oceanic arc” end member subduction zone, and allows study of arc processes without the complicating effects of thick, geochemically distinct continental crust. The timing for the workshop reflected the five years since the last IBM workshop and the approaching end of the current MARGINS program. The meeting also explored results and opportunities related to the International Ocean Drilling Pro-gram, US NOAA “Ocean Exploration” program and research related to the “Law of the Sea” by the US and Japan. The meeting’s success was due mostly to the synergy of these diverse research perspectives.

Workshop Structure

Workshop goals were to discuss re-sults from the first seven years of MAR-GINS-funded research in IBM, present recent advances in databases and educa-tion efforts, and discuss future research plans. The meeting brought together sci-entists from a wide variety of disciplines engaged in activities such as geophysical imaging, geodynamical modeling, geo-logical and bathymetric mapping, iso-tope geochemistry, and the quantification of volatile fluxes. Recent US and Japa-

nese expeditions have generated exciting new data sets, and in many cases this meeting provided the first opportunity to present, discuss, and compare these results. Most of the 104 participants came from the US and Japan (66 and 26 par-ticipants respectively). Others came from Australia, China, South Korea, Czech Republic, Germany, Mariana Islands, Canada and the UK. Fifteen graduate students and nine post-doctoral scien-tists participated. Workshop conveners were Patty Fryer, Shuichi Kodaira, Jeff Ryan, Bob Stern, Yoshi Tatsumi, and Douglas Wiens. The workshop was supported by the US National Sci-ence Foundation MARGINS Program and by IFREE-JAMSTEC (Japan).

The meeting opened with brief intro-ductory comments by Bob Stern (goals of the meeting), Geoff Abers and Yoshi Tatsumi (MARGINS and IFREE back-ground) and Brian Midson (NSF per-spective). The next 2.5 days were spent presenting and discussing new results and syntheses for the IBM arc. Keynote presentations on informational advances in the IBM subduction factory over the past 5 years were organized into the fol-lowing 7 thematic sessions (speakers in parentheses):

Workshop Report

1) History of the region (Gurnis, Ohara)2) Geodynamic modeling (Conder, van Keken, Baker)3) Inputs and volatile cycling (Kelley, Shaw, Butterfield, Fryer)4) Education and infrastructure, includ-ing hazards (Ryan, Lehnert, Tsuboi, Murray, Camacho)5) Large scale geophysical imag-ing (Kawakatsu, Wiens, Nakajima, Seama)6) Arc geochemistry (Ishizuka, Gill, Pearce)7) Crustal Imaging and Crustal Growth (Kodaira, Calvert, Tatsumi, Kelemen, Arculus)

Powerpoint presentations are at www.nsf-margins.org/IBM07/presentations.html. Most workshop participants put up posters which were viewed during breaks and evening poster sessions. Many of them can be downloaded from www .nsf-margins.org/IBM07/posters.html. Another evening session discussed da-tabases (Andrew Goodwillie and Kirsten Lehnert) and Science Education related to Subduction Factory (Jeff Ryan). The last half-day was spent in break-out groups, discussing where progress has been made as well as what needs to be accomplished in order to understand the IBM system.

Smaller Group Discussions

Discussion groups addressed the following themes: 1) Tracing the flow of matter and energy through subduc-tion zones; 2) Volatile cycling through subduction zones; 3) Subduction and the development of continental crust; 4) Subduction initiation; 5) Education and databases; and 6) Infrastructure and hazards. Summaries of new develop-ments in these areas highlighted by the keynote speakers and the resulting group discussions are provided below.

Figure 1. Explosive hydrothermal vent activity at NW Rota-1, southern Marianas. Image courtesy of Bob Embley and the NOAA Ocean Exploration program.

MARGINS Newsletter No. 20, Spring 2008 Page 13

1) Tracing the Flow of Matter and En-ergy through Subduction Zones One of the main emphases of the Subduction Factory initiative is under-standing material transport and pro-cessing. For this geophysical imaging is especially useful, and exciting new images, generated by US-MARGINS and Japanese studies, were presented. D. Wiens showed new tomographic im-ages of the mantle wedge, obtained us-ing data from the 2003-2004 US-Japan ocean bottom seismograph deployment, that reveal regions beneath the Mariana magmatic arc and backarc spreading center with low seismic velocity and high attenuation. These features extend down ~100 km and may reveal where mantle melts. N. Seama presented new electrical conductivity images obtained from the 2005-2006 international magnetotelluric transect, which show low conductivity beneath the forearc, arc, and backarc spreading ridge. The low conductivity feature extending to 50 km beneath the forearc likely represents hydrous fluids following channels to feed serpentinite seamounts. A narrow feature beneath the backarc in both the seismic and conductivity results suggests a focused zone of mantle upwelling beneath the spreading center. Shear wave splitting results suggest that shallow mantle flows along-strike in the mantle wedge, and P. van Keken and J. Conder discussed geodynamic models that could produce along-strike mantle flow. Geochemical and isotopic studies have advanced our understanding of

how arc and backarc magmas are gener-ated. It appears that arc magmas often include melts of subducted sediments and/or altered oceanic crust, but there are many uncertainties about this com-ponent. J. Gill’s presentation explored the observation that enriched Th and Nd isotopic compositions are not restricted to sediment melts. Geochemical studies also show that fluids and melt can move through the system at rates much faster than typical mantle processes. Progress in our understanding how this component moves from the slab to the region of melt generation requires development of better 3-D geodynamic models, by laboratory studies to better constrain the pressure-temperature-composition variations in mineral and fluid partitioning, and by better constraints on the relationship of seismic measurements to properties such as melt and water content. Such advances are needed to guide the further development of geodynamic models that include fundamental arc processes such as melt generation, as shown by L. Baker. 2) Cycling of Volatiles through Sub-duction Zones One of the major contributions of the IBM subduction factory experiment is a greatly improved understanding of how volatiles move through subduction zones. Scientific ocean drilling has been crucial in this effort, allowing the characteriza-tion of volatile inputs from the incoming Pacific plate (K. Kelley). Furthermore, outputs from the system have been char-acterized in terms of gases from active

vents along the volcanic arc and from pre-eruptive magmatic volatile contents (glass inclusions in especially olivine phenocrysts), as described by A. Shaw. A powerful new perspective on IBM Subduction Factory outputs was provided by NOAA’s Ocean Exploration program (D. Butterfield). NOAA technology was adapted to identifying hydrother-mal vents on the arc. Subsequent ROV dives on selected sites in the Mariana arc discovered a variety of submarine arc fluxes, from an erupting volcano to bubbling CO2 vents to seafloor ponds of molten sulfur. However, inputs are incompletely characterized because it is unknown if the incoming lithospheric mantle carries sig-nificant water. Geophysical studies of the incoming plate beneath Central America suggest that bending near the outer trench bulge generates deep normal faults that allow seawater infiltration and serpen-tinization of the upper mantle. Similar processes beneath the incoming Pacific plate would carry tremendous amounts of water into the IBM subduction zone. This problem could be addressed by a geophysical experiment designed to identify serpentinite produced beneath the IBM outer trench bulge. Much mystery still surrounds output fluxes, including where volatiles might be stored between the subducted slab and the surface and the extent to which volatiles and incompatible lithophile elements move together or fractionate. For example, there are pathways in the forearc that capture volatiles lost from the subducting plate, but what is the extent to which the forearc mantle is serpen-tinized? Discoveries show purported water proxies in subduction factory mag-mas (e.g., Ba/La, U/Th, etc.) in fact do not follow water, as shown by A. Shaw and K. Kelley, but it is not clear why. Studies of forearc serpentine mud volcanoes provide unique perspectives on fluid outputs. Drilling of IBM ser-pentinite diapers is on the IODP sched-ule, pending FY09 budget guidance. Monitoring of the actively erupting NW Rota-1 is needed, and NSF has tentatively

Figure 2. Participants from the Workshop. Photo taken by Teruaki Ishii.

Page 14 MARGINS Newsletter No. 20, Spring 2008 Workshop Reportapproved a proposal by Chadwick et al. to revisit it.

3) Subduction processes and the devel-opment of arc crust Intra-oceanic arcs like IBM allow us to extrapolate from the formation of mod-ern arc crust to the growth of continental crust. To understand how arc crust might become continental crust, the complete magmatic evolution of an arc system must be investigated. Geophysical and geochemical perspectives are required: seismic reflection/tomographic studies of the IBM arc, and geologic, petrologic, and geochemical comparisons to other arc sections. S. Kodaira presented the results of Japanese efforts to seismically image Izu-Bonin arc crust. This identified thickened lower velocity (tonalite) layers beneath basaltic volcanoes, suggesting that the development of tonalitic midcrust was related to modern arc processes. In contrast, A. Calvert presented a seismic velocity model for Mariana arc crust that indicated a greater abundance of evolved intrusive rocks beneath the fossil Eocene arc than beneath the modern arc. Significant strides have been made in understanding how IBM arc compo-sitions evolve. Y. Tatsumi synthesized geophysical results with petrologic modeling to demonstrate that IBM seis-mic structure can be explained through basaltic magmatism, accompanied by reprocessing of mafic crust, resulting in crust with a shallow tonalitic zone and underlying mafic residuum; for-mation of bulk andesitic crust requires delamination of higher density restites. Comparisons to the Talkeetna (Alaska) arc intrusive sequence, presented by P. Kelemen, indicated gross similarities to IBM crustal structure and the necessity for delaminating dense mafic/ultramafic cumulates. Further probing of arc processes requires deep arc crustal drilling and geophysical studies. An example of this is the proposed 8 km IODP drilling into northern IBM arc crust (IODP 698). This borehole should be complemented by drilling rear-arc crust (proposed in

IODP 697), which is greatly enriched in LIL elements and provides the “missing half” of arc crustal studies. 4) Subduction zone initiation The IBM system is a superb location for investigating how new subduction zones form. IBM subduction initia-tion models fall into one of two general classes: spontaneous collapse of old Pacific lithosphere and forced subduc-tion initiation. Resolving the “IBM sub-duction initiation controversy” requires understanding uplift/subsidence history preserved in older terranes. Spontane-ous initiation predicts early subsidence, whereas forced initiation predicts early uplift. Drilling in thick sediments of Amami Basin to the west of the Kyushu-Palau Ridge (proposed as IODP 695) would test these models. Crust generated during the subduc-tion initiation event was created almost synchronously by seafloor spreading as subduction began, ~48 Ma ago, and is

remarkably well-exposed in the forearc. Drilling IBM’s forearc would allow us to study “infant arc” crust, as demon-strated by ODP 786B, which penetrated 800 m into tholeiitic and boninitic lavas and dikes. This hole is stable and should be deepened to penetrate into the sub-jacent gabbro, as is proposed in IODP 696. Geophysical studies of the forearc are hampered because serpentinization makes the Moho difficult to identify seismically, so JAMSTEC is planning new field studies designed to better image crustal structure. Complementary efforts to understand how subduction began in the southern IBM arc system will eventually be needed as well. Crustal drilling on Guam would provide a cost-effective opportunity to obtain deep arc crust samples. Seismic surveys on Guam and in the Guam region are needed to quantify arc crust composi-tion and thickness in this region and to provide a comparison to the imaging of Izu arc crust.

Figure 3. Seismic attenuation 1000*QP-1 tomography at ~18ºN from the MARIANA seismic

experiment. Triangles at the top indicate the locations of the West Mariana Ridge (WMR), Mariana Spreading Center (SC), Volcanic Front (VF), and Big Blue (BB) forearc serpentinite seamount; black circles are earthquakes used in the study. Distinctly separate regions of high attenuation are observed beneath the spreading center and volcanic front, connecting only near ~100 km depth. In addition, a moderate attenuation region is observed beneath the serpentinite seamount.

VF BBSCWMR

1000/QP

0 100 200 300 400 500 600 700

0

50

100

150

200

250

300

350

400

0 5 10 15 20 25

MARGINS Newsletter No. 20, Spring 2008 Page 15

A) Test the Outer Trench Bulge Serpentiza-tion Hypothesis

Critical evaluation of the hypothesis that significant amounts of water are added to the downgoing plate beneath the outer trench bulge is needed to understand how the Subduction Factory operates. Geo-physical surveys of the upper mantle be-neath the outer trench bulge should be able to evaluate the amount of bending-related serpentinization, if any. Simultaneously, we should advance analytical techniques designed to identify the isotopic and geo-chemical expression of fluids derived from subducted serpentinites, such as Li, B, and some halogens. The effort to test the outer bulge serpentinization hypothesis would be a natural avenue for continued US-Ja-pan collaboration to understand the IBM Subduction Factory. This effort will also inform subduction initiation models, since the force needed to bend the plate – a criti-cal element of subduction initiation models – is greatly reduced if the plate contains a significant proportion of serpentinite.

B) Understand the Extent of Fluid Flow and Mantle Serpentization in the Forarc

There have been many observations of serpentinite seamounts in the IBM forearc, but little is known about the extent of fluid flow and serpentinization at deeper levels. Seismological studies are needed to quan-tify the degree of mantle serpentinization as a function of depth and location in the forearc, and seafloor observing networks can quantify fluid flow rates, the biological activity associated with fluid flow, and its temporal relationship to earthquakes.

C) Develop Accessible Quantitative Models for Subduction Zone Input and Output

Continued development of physically realistic 3-D plate models coupled with an understanding of subduction zone thermal and rheological structures permits appli-cation of thermodynamically appropriate mineralogic and fluid evolution models. Fluid transport needs to be explored with realistic models. All of these features can be modeled and we should continue to develop such internally self-consistent models, which can then be tested for IBM and Central America as well as for other arc systems.

5) Education and Databases Part of the second day was devoted to MARGINS education and database activities, followed by education-related posters in the afternoon, and a series of “breakout” sessions each evening. J.Ryan introduced the MARGINS Sci-ence in the Classroom project, a collab-orative effort funded by the NSF Course Curriculum and Laboratory Improvement (CCLI) Program to adapt the growing body of MARGINS data for use in un-dergraduate geoscience courses. Fifteen MARGINS “Mini-Lessons” are available at http://serc.carleton.edu/margins/col-lection.html, and an objective of this proj-ect is to generate a thematically linked set of Mini-Lessons focused on the IBM subduction system. K. Lehnert presented information on the various MARGINS data repositories: The Marine Geosci-ence Data System and the Geoinformat-ics for Geochemistry (GfG) geochemical data repositories, both housed at LDEO. S. Tsuboi presented the approaches to data management and visualization being used at JAMSTEC/IFREE, which involve making use of Google Earth as a global visualization tool. Workshop participants were introduced to GeoMapApp, the Java-based GIS tool maintained by the Marine Geoscience Data System, and to the PetDB and SedDB geochemical databases. There were also discussions of ways to exploit outlets such as Google and Wikipedia, where relatively modest efforts would reach global audiences. 6) Infrastracture and Hazards Geological hazards are a significant concern for people living on islands in the IBM system, including risks from volcanoes, earthquakes, tsunamis, and landslides. Also, as regions adminis-tered by the US and Japan, governmental agencies have a responsibility to assess and mitigate these hazards to the extent possible. Thus there was discussion at the meeting about how other scientists can help with this effort. T. Murray outlined USGS plans to expand their volcano monitoring efforts in the Northern Mariana Islands, includ-

ing plans for a VSAT telemetry node and transmitter on Pagan Island, and additional real-time seismic stations on surrounding islands. J. Camacho of the Saipan Emergency Management Agency also participated in these discussions. Some equipment has been purchased by the USGS but funding has not yet become available for installation and operation. An evening breakout session attended by the USGS, NOAA, and Saipan EMO representatives as well as interested academic scientists discussed the needs and opportunities involved in hazard monitoring.

Publication

A volume of recent results of IBM re-search is planned. This will complement the G-cubed volume for Central America Subduction Factory results. The volume will be edited by S. Kodaira, S.Pozgay, and J. Ryan.

Recommendations

The workshop recognized that un-derstanding IBM and other subduction factories is key for understanding the Earth system. Future efforts should build on the current success by applying advanced technological techniques, and emphasizing international co-ordina-tion of research efforts and integration of scientific results. Joint efforts should encourage development of formal and informal collaborations between IODP and MARGINS-successor efforts in the region. Continued emphasis on using IBM research results to teach better about subduction zones in K-16 classrooms is a high priority, as is continued co-ordina-tion between researchers and database developers. Some of the specific rec-ommendations for future research are summarized as follows:

Page 16 MARGINS Newsletter No. 20, Spring 2008

Recent advances in understanding the rifting process have come from stud-ies in the MARGINS Initiative on Rift-ing Continental Lithosphere (RCL) fo-cus site in the Gulf of California as well as through other MARGINS and non-MARGINS funded projects in many rifts. Because the MARGINS program is approaching the end of its first de-cade (2009), a workshop was held the day before the Fall 2007 AGU meeting in San Francisco to discuss the future of the RCL initiative. The purpose of the meeting was to: (1) evaluate recent progress in studies of rifting continental lithosphere, both within the MARGINS Program focus site and in other areas and (2) to begin considering possible fu-ture directions of RCL within a second decade of MARGINS.

The workshop brought together about 50 geoscientists who work on the processes and sites of rifting conti-nental lithosphere. The program began with a brief review of the advances in research in the Gulf of California focus site. There was general agreement that significant advances had been made in understanding the rifting history and structure of the Gulf of California. New data challenges older ideas on the dis-tribution of strain during the opening of the southern and central Gulf. Specifi-cally, it appears unlikely that the early opening of the Gulf occurred via only orthogonal rifting within the Gulf and strike-slip motion may have been con-siderably less west of Baja California; that is, the Gulf may have had major transtensional deformation throughout its history. Seismic work shows surpris-ing variability in the pattern of crustal thinning in the sub-basins of the rift

along the rift trend and this has been linked to the pre-rifting magmatic arc history of the region. There is consid-erable excitement over the opportunity to extend the seismic investigations to the north of the Gulf into the Salton Sea/Trough and a project to do that has been jointly funded by MARGINS and EarthScope.

There was brief discussion of the sta-tus of research in several rifts around the world, RCL-related modeling, and of the need for IODP drilling of rifted mar-gins. The political and logistical diffi-culties of working in the Red Sea and in East Africa were highlighted.

Among the theoretical and modeling topics discussed, there was particular in-terest in the role of magmatism during rifting. The links between tectonics, cli-mate and landscape evolution and sedi-mentation is also an area where the RCL community needs input from colleagues in those related fields.

The workshop participants consid-ered whether the “focus site” paradigm is the best for RCL in the future, and how best to get broader community input

into the RCL planning process. There was no consensus as to whether a future MARGINS Program should be built around a small number of geographi-cally defined “focus sites” where ob-servational and modeling efforts would be directed or whether a few scientific “themes” should be the focus of efforts in studying a number of rifts. These 2 strategies are not mutually exclusive and there may be ways that they can be combined.

There was consensus that the first step in planning for any renewed effort in MARGINS RCL would involve a community effort to prioritize the most important questions that need to be ad-dressed and proponents could propose experiments anywhere that these themes could best be studied. There was also agreement that the current constraints on MARGINS research (only active sites; rift to drift sites; mainly marine science; 2 focus sites) should be changed. The idea of studying rifts that are not now active was met with wide approval.

RCL Workshop Report

MARGINS Workshop Report:

“The Future of the NSF-MARGINS Initiative Rifting Continental Lithosphere (RCL)”

San Francisco CA, December 9, 2007Co-conveners: Paul Umhoefer (Northern Arizona University)

Roger Buck (LDEO, Columbia University)

NSF-MARGINS Proposal Deadline:

The next NSF-MARGINS and

Post-Doctoral FellowshipProposal Deadline is July 1st, 2008

MARGINS Newsletter No. 20, Spring 2008 Page 17

Status Report on the MARGINS Data Portal ~ April, 2008Andrew Goodwillie and the MARGINS Database Team

Lamont-Doherty Earth Observatory, Columbia University The MARGINS database group

(www.marine-geo.org/margins) would like to thank the following investiga-tors for contributing information and data since the last newsletter report for a number of MARGINS-funded field programs.

In the Central America Focus Site, rock sample information and geochemi-cal data for Jim Walker’s 2004 Guatemala field program were added. We incorpo-rated from Peter Lonsdale shipboard digital data, including EM120 multibeam bathymetry swath files, gravity and magnetics for his 2003 Revelle cruises DANA01RR and DANA02RR. The grid-ded multibeam bathymetric compilation of Wili Weinrebe and Cesar Ranero, and Udo Barckhausen’s magnetic anomaly compilation have been added and are accessible through GeoMapApp for the Central America site.

In the IBM area, Rob Evans (WHOI), along with chief scientist Nobukazu Seama (Kobe University) and Yaunori Hanafusa (JAMSTEC) provided cruise information, navigation data and details of magnetotelluric station deployment and recovery operations for Kairei cruis-es KR05-17 (Dec. 2005), KR06-12 (Sep. 2006) and KR07-16 (Nov. 2007). Raw and processed Jason II ROV navigation files for Patty Fryer’s 2004 rock sampling cruise TN154 are now available. Jim Gardner has supplied cleaned data for his US Law of the Sea bathymetric survey over the West Mariana Ridge and Parece Vela Basin. Geochemical data files are available for Mark Reagan’s Marianas Forearc work and for Terry Plank’s IBM samples.

For the Gulf of California Focus Site, gravity/magnetics and EM120 swath bathymetry data from Peter Lonsdale are now available for his 2004 Revelle cruises DANA07RR and DANA08RR.

For three of the Melville cruises in 2004 to Papua New Guinea - VANC-24MV, VANC25MV, and VANC26MV - Larry Peterson provided information

on dredge rock samples, plankton net biological samples, CTD stations and sediment cores. SeaBeam multibeam bathymetry and sidescan data, along with sub-bottom, ADCP and XBT data are also available. For Neal Driscoll’s VANC22MV and VANC23MV cruises, also from 2004, 3.5 kHz sub-bottom data files are available.

In the New Zealand Waipaoa Source-To-Sink area, Clark Alexander and Steve Kuehl contributed raw EM120 and EM1002 multibeam swath files, CHIRP sub-bottom data, CTD and ADCP data and references for their early 2005 cruises KM0502 and KM0503. Compila-tion bathymetric and sidescan grids and images derived from the EM120 and EM1002 data are also available. These 50m, 20m and 4m bathymetry grids and 15m sidescan grids can also be accessed through GeoMapApp for the New Zea-land Focus Site.

Education and Outreach

Highlighting data collected in vari-ous MARGINS Focus Sites, we had an exhibit booth and ran a lunchtime work-shop on data resources at the annual GSA meeting in 2007 (Oct., Denver). With MARGINS sponsorship we ran a MAR-GINS-focused data resources workshop in San Francisco in December 2007, and talked in an education session dur-ing the Fall AGU meeting. For the IBM workshop (Nov. 2007, Honolulu) data-base demonstrations were given during education break-out sessions. Examples of MARGINS database resources were presented during a number of sessions at the SERC-sponsored workshop Teaching with New Geoscience Tools (Feb 2008, UMass Amherst). At the 2008 Ocean Sciences meeting (March, Orlando), we participated in the MARGINS Source-To-Sink education mini-lessons work-shop convened by Jeff Ryan. An update on database activities was presented to the MARGINS Steering Committee (Nov. 2007, Honolulu).

GeoMapApp Updates

Improvements and enhanced flexibil-ity have been added to GeoMapApp, the platform-independent Java™ application for exploring and visualizing data (down-load for free from www.geomapapp.org). Users are now offered a wider range of options for importing grids and data tables and for saving grids and images. A panning icon can be used to move the basemap. A new option allows UTM grids to be imported and profiles can now be taken across any type of imported grid. The multi-channel seismics interface and multibeam file download capability have been improved. The MGDS Global Multi-Resolution Topography (GMRT) which underlies GeoMapApp has been updated with new swath bathymetry. Sed-iment geochemistry data in the SedDB database (www. seddb.org) can now be viewed seamlessly in GeoMapApp using Web Feature Service technology. Links to International Heat Flow Commission (IHFC) continental and oceanic heat flow data were added for each Focus Site.

We welcome new contributions of data from your MARGINS-funded work. A packet of standardised metadata forms to capture information for the database on the land-based field programs and cruises is available for download from www.marine-geo.org/metadata_forms.html. For upcoming field programs, we ask PIs to identify one person who will be responsible for liaising with the MARGINS database group for the field program. Contact us (www.marine-geo.org/contact.html) prior to your upcom-ing field expedition and we will help identify what metadata forms are needed to document your field program. We are actively seeking contributions from land programs and for older programs, both marine and land.

Database Report

Page 18 MARGINS Newsletter No. 20, Spring 2008 MARGINS Future

Dear MARGINS Community,

As many of you know, the NSF MARGINS program was conceived as a decadal program, and that decade ends in 2009. To date, MARGINS has seen a great deal of success, in major scientific discoveries, truly cross-disciplinary scientific communities, and in driving science across a range of programs. A major review is currently scheduled to occur in 2009, and the program in its present form will begin to wind down. A viable successor program will have to be well-argued and driven by major, transformative science endeavors that cannot be accomplished through core funding. We are writing this letter to engage the community in a planning process, and to highlight several ways in which you can get involved.

A) Integration and synthesis propos-als.

The MARGINS Science Plans call for integration and synthesis of results in all Initiatives and, ideally, across Initiatives, a call that was strongly reinforced by a mid-program review in 2004. Cross-disciplinary integra-tion is one major way to distinguish MARGINS as a coherent program. Studies to integrate and synthesize results are well within the scope of the Science Plans and hence within the scope of what could be funded through the MARGINS NSF solicitation (July 1 deadline). We highlight this oppor-tunity, and bring it to the attention of anyone who might consider seeking support for an integrative project.

B) Self-organized planning groups.

The MARGINS Steering Commit-tee (MSC) encourages self-organizing groups to formulate potential directions for the future. This is especially impor-tant for programs not now represented in MARGINS. Such an effort could be independent of, but parallel with, preparations for the decadal review. Being pro-active in exploring and evaluating future directions is prob-ably the best way to maximize the likelihood of a positive outcome. Any groups interested in self-organizing a planning function should provide an outline of what they would like to do, and contact an MSC member or the Chair (abers@nsf-margins.org) to dis-cuss how to proceed, preferably before April 2008. Again, the nature of any successor program could be quite dif-ferent than the current MARGINS. The current definitions of Initiatives and Focus Sites (or even the idea of Focus Sites) are not constraints. For example, there has been much discussion already about the merits of a Thematic rather than Focus Site structure to a succes-sor program, and about emphasizing hazards or resource-related science at active and passive margins (see Chair’s Comments in Fall 2007 MARGINS Newsletter, just published).

Shortly after AGU, we plan to open up a web-based forum for posting informal idea pieces and white papers on potential future di-rections of the program [see p. 8]. C) MSC-organized planning activi-ties.

The MSC is actively recruiting groups to participate in and run plan-

ning activities at a variety of levels over the coming months. Various committee members have been active in bringing together other groups, for example in thematic planning workshops. One example is the RCL Future workshop at AGU this December. We envision a set of straw-man ideas developed over the coming months that could illustrate some of the potential of a successor program, with in-depth science plans developed after such a program is approved. By the time the current pro-gram is reviewed, some clear models for a potential future program should be outlined.

D) Science.

The current NSF MARGINS pro-gram is accepting proposals for annual July 1 deadlines (see NSF solicitation 07-546). The program has been steadily funded for the last several years, with successful proposals in all Initiatives. The Post-Doctoral Fellowship pro-gram continues to be supported, and is described in the same solicitation. Now is a great time to begin thinking about science proposals to submit for next July.

If you wish to discuss this with any of us, our contact information is available on the MARGINS web page (www.nsf-margins.org/MARGINS_Office/AboutSC.html). Also, many members will be present at AGU, at the annual MARGINS Reception Monday Dec. 10, 6-8 pm, Marriott Salon 7, and will be happy to discuss these issues with you.

Regards,The MARGINS Steering Committee

Open Letter From the MARGINS Steering Committee: On the Future of MARGINS

November 28, 2007

MARGINS Newsletter No. 20, Spring 2008 Page 19

MARGINS-Themed Special Issues and BooksUpcoming Special Issues

“The Central American Subduction System” (G. Alvarado, K. Horenle and E. Silver, eds.), Special Theme of Geochem. Geo-phys. Geosyst. Accepting contributions now. www.agu.org/journals/gc

“The Izu-Bonin-Mariana Subduction System: A Comprehensive Overview” (S. Kodaira, S. Pozgay and J. Ryan, eds.), Special Theme of Geochem. Geophys. Geosyst. Accepting contributions now. www.agu.org/journals/gc

“From Mountains to Abyss – Sedimentation along Source to Sink Pathway of the Waipaoa Sedimentary System” (L. Carter and S. Kuehl eds.), Special Volume of Mar. Geol., Expected Publication late 2008.

Recently Published Special Issues “The Papuan Continuum: Source to Sink through the Fly River System and the Gulf of Papua”, J. Geophys. Res., Vol. 113, No. F1, March 2008 (C. Nittrouer, R. Slingerland, and J. Dickens, eds.) www.agu.org/contents/sc/ViewCollection.do?collectionCode=PAPUA1

“The 2003 Eruption of Anatahan Volcano, Commonwealth of the Northern Mariana Islands (CNMI)”, Special Issue of J. Volca-nol. Geotherm. Res., Vol. 146, Issues 1-3, Aug. 2005 (D.R. Hilton, J.S. Pallister and R.M. Pua, eds.)

“Arenal Volcano, Costa Rica- Magma Genesis and Volcanological Processes”, Special Issue of J. Volcanol. Geotherm. Res., Vol. 157, Issues 1-3, Sept. 2006 (J. Gill, M. Reagan, F. Tepley and E. Malavassi, eds.)

MonographsThe Seismogenic Zone of Subduction Thrust Faults (T.H. Dixon and J.C. Moore, eds.), Columbia Univ. Press, MARGINS Theor. and Exper. Earth Sci. Ser. vol. 2, 692 pp, Sept. 2007.www.columbia.edu/cu/cup/catalog/data/978023113/9780231138666.HTM

Imaging Mapping and Modelling Continental Lithosphere Extension and Breakup (G.D. Karner, G. Manatschal and L.M. Pinheiro, eds.), The Geological Society, Spec. Pub. 282, 488 pp., July 2007.www2.geolsoc.org.uk/template.cfm?name=bookshop_details&id=803&CFID=4450145&CFTOKEN=c3e6956e3f85a00d-02F11FF4-1125-29BA-709F4B94584EB290

Rheology and Deformation of the Lithosphere at Continental Margins (G.D. Karner, B. Taylor, N.W. Driscoll and D.L. Kohlstedt, eds.), Columbia Univ. Press, MARGINS Theor. and Exper. Earth Sci. Ser. vol. 1, 384 pp, Feb. 2004.www.columbia.edu/cu/cup/catalog/data/023112/0231127383.HTM

Inside the Subduction Factory (J. Eiler, ed.), Amer. Geophys. Un. Geophys. Monogr. ser., vol. 138, 324 pp., 2004.www.agu.org/cgi-bin/agubookstore?book=SEGM1389973&search=subduction%20factory

Go to www.nsf-margins.org/Books.html for more details.

The Seismogenic Zone of Subduction Thrust Faults

Timothy H. DixonJ. Casey Moore,EDITORS

Page 20 MARGINS Newsletter No. 20, Spring 2008 Post-Doc Program

Apply for the NSF MARGINS Post-Doctoral ProgramApplications due at the regular July 1 NSF deadline

For details, see the NSF program announcement and www.nsf-margins.org/PostDoc.html

Past recipients since program inception (2003)2007 • Ben Holzman, Deciphering the Role of Melt Segregation and Strain Partitioning in Rifting Continents, Columbia University.2006 • Jeremy Boyce, Exploring the Record of Magmatic Volatiles in a Volcanic Arc via H, C, F, S, and Cl in Apatite, Arizona State University.2004 • Jennifer Garrison,Time-scalesandmechanismsofdifferentiationofmaficparentstorhyodaciteinCentralAmerica,Uni-versity of Iowa. Now Assistant Professor at California State University, Los Angeles.2003 • James Conder, A Numerical Investigation of the Relative Importance of Different Melting Mechanisms at Volcanic Arcs, Washington University, St Louis. Now Senior Research Associate, Washington University, St. Louis.2003 • Alison Shaw, Constraining the Volatile and Slab Flux in the Izu-Bonin-Mariana MARGIN Using Geothermal Fluids, Pheno-crysts and Melt Inclusions, Carnegie Institution of Washington. Now Assistant Scientist, Woods Hole Oceanographic Institution.

2003 • Glenn Spinelli,Theroleofsedimentdiagenesisanddewateringonfluidandheatflow,CostaRicamargin,Univ.Missouri-Columbia. Now Assistant Professor, New Mexico Tech.

MARGINS Postdoctoral Program: BiographySince 2003, the MARGINS program has funded a number of post-doctoral fellows, both within the special MARGINS Post-Doctoral Fellowship and within the regular NSF-MARGINS programs. This article profiles post-doctoral fellow Heather Savage.

Heather SavageNSF Award 0742242University of California, Santa CruzMARGINS FELLOWSHIP: The effect of frictional properties in subduction zones on earthquake triggerability

I recently began work on my NSF-MARGINS postdoc at the University of California, Santa Cruz with Emily Brodsky comparing the triggering po-tential of subduction zones and relating differences in triggerability to fault zone architecture. To date, my research has generally focused on the complex be-havioroffaultsusingexperiments,field-work, and theory. During my Master’s with Michele Cooke at the University of Massachusetts, Amherst, I was very interested in questions of fault interac-tions over long time periods and how these interactions could affect structures such as overlying folds. I became inter-ested in shorter time scale interactions and fault friction behavior during my

Ph.D. with Chris Marone at Penn State. Using the biaxial deforma-tion apparatus in the Penn State Rock and Sedi-ment Mechanics

lab, I conducted stick-slip friction ex-periments on bare rock and granular ma-terial to assess how oscillating stresses such as seismic waves and tides trigger seismicity. To do this, I applied a small oscillating shear velocity on a constant shear loading rate to mimic seismic stresses superimposed on tectonic rates. These experiments indicated that the presence or absence of a fault gouge layer (or any granular material in a shear zone) changed the sensitivity of a fault to earthquake triggering. In bare rock surface experiments the roughness of the surfaces determined sensitivity to triggering, whereas in the granular layer experiments, layer thickness determines triggerability. The bare rock experi-ments can be interpreted as immature

faults where asperity contact determines fault strength, while the granular layers model mature faults with well-devel-oped gouge zones. If the analogy holds, Ipredictthatfaultmaturityshouldinflu-ence triggerability. For my MARGINS postdoc, I will test this hypothesis on the largest scale possible: subduction zones. Beneath Costa Rica, the seafloor be-ing subducted is dotted with seamounts and ridges that act as asperity contacts with the overriding plate. Presumably, we should see a difference in trigger-ing potential between this subduction zone and others. By looking at trigger-ing events of similar sizes in different subduction zones, I aim to assess which areas are more sensitive to changes in stress. To do this, we will search for lo-cally triggered events during the passage of seismic waves from large, remote events, as well as counting the number of aftershocks from local events. I am excited to have this opportunity to learn some observational seismology and ap-ply my ideas to real world observations.

MARGINS Newsletter No. 20, Spring 2008 Page 21

2007 AGU Fall Meeting, Dec 10-14, San Francisco Congratulations to all those who entered our fifth annual student com-petition, which took place at the AGU 2007 Fall Meeting. As in previ-ous years, the judges were impressed by the quality of all entries. We recognize here the outstanding entries that received the highest scores by our judges.

The MARGINS Prize accepted entries from students in any nation who could establish a link between their research and a stated aim of a MARGINS Program Initiative. The winners and honorable mentions reflect the breadth of the field, representing several countries, gender diversity and the four MARGINS initiatives.

Our thanks go to the judges and to the students who entered. Togeth-er, it is their efforts that make the MARGINS Student Prize possible. We are also grateful to AGU for their cooperation and assistance with logistics before, during and after the meeting.

Oral Presentation Winner:

Kimberly Psencik, University of Mi-ami, FL

Student’s Comment:

“I am so honored to have been selected as the winner of this years’ MARGINS prize. Thank you to NSF and MARGINS for making this research possible. I am humbled to have been recognized by such an outstanding scientific community and excited to continue my research and help further the initiatives of MARGINS.”From the Judges:Exciting science. Very interesting results. Excellent presentation and graphics.Title of Abstract:Current Status and Future Directives of the Nicoya Peninsula Continuous GPS Network, Costa Rica, In Regard to Slip Style and Distribution. (G23A-04)Co-Authors:Y Jiang, P C LaFemina, T H Dixon, M Protti, V Gonzalez, J Skylar, F Blume

Poster Presentation Winner:

David Abt, Brown Univer-sity, RI

Student’s Comment:“It is a real honor to have my research acknowledged among the many excel-lent MARGINS-related presentations at AGU. I am very grateful to have been involved in the MARGINS Program, which, along with the Student Prize competition, provides a wonderful venue for students to share their research with others in the MARGINS community.”From the Judges:Clearly knows his stuff. Understands science at post-doc level. Very enthu-siastic!Title of Abstract:Resolving Three-Dimensional Anisotro-pic Structure with Shear-wave Splitting Tomography. (S23B-1371)Co-Author: K M Fischer

Honorable Mentions:

Kimberly Genareau, Arizona State University, AZ

Student’s Comment:“I appreciate the recognition I received and I look forward to conducting MAR-GINS research in my future career.”From the Judges:“One of the best student presentations. Novel, interesting topic. Excellent delivery.”Title of Abstract:Constraining Pre-eruptive Pressure/Tem-perature Variations, Transition From Chamber to Conduit, and Crystal Growth Rates: a SIMS Examination of Plagio-clase Phenocrysts. (V22A-05)Co-Authors:A B Clarke, R L Hervig T. Ishii

Zunli Lu, Rochester University, NY

Student’s Comment:“It is a great pleasure to be honored by MARGINS for this talk. Hope my future work will continue to make contributions to your program.”From the Judges:Interesting science. Engaging, very clear speaker.Title of Abstract:The iodine release during organic matter degradation at Northern Cascadia Mar-gin: a numerical approach. (OS11C-06)Co-Authors:C Hensen, U Fehn

Spotlight on Education

MARGINS Student Prize for Outstanding Presentations

Page 22 MARGINS Newsletter No. 20, Spring 2008

The Subduction FactoryPeter Kelemen

Peter is Arthur D. Storke Professor at Columbia University, Associate Research Scientist at the American Museum of Natu-ral History, and Adjunct Scientist at Woods Hole Oceanographic Institution.Public Lecture: a) Origin and evolution of continental crust; b) The future of geologi-cal exploration: Why, and how?Technical: a) Arc lower crust: The Talk-eetna Continental Dynamics Project; b) A viscous shear heating mechanism for intermediate depth earthquakes.

Simon KlempererSimon is a Professor of Geophysics, and

by courtesy of Geological and Environ-mental Sciences, at Stanford University.Public Lecture: Building continental crust in the Subduction Factory; Technical lecture: Crustal structure and evolution of the Mariana intra-oceanic island arc.

The Seismogenic ZoneTim Dixon

Tim is a Professor of Marine Geology and Geophysics at the University of Miami.

Public lecture: Unraveling Earth’s Largest Earthquakes Using Space Techniques; Technical lecture: Comparing Short and Long Term Deformation as Recorded by Geodesy and Geology.

Greg Hirth Greg is an Associate Scientist at Woods

Hole Oceanographic Institute.Public lecture: Understanding earthquake processes at the microscopic scale; Technical lecture: The rheology of real rocks.

Source-to-SinkPatricia Wiberg

Pat is a Professor in the Department of Environmental Sciences at the University of Virginia.Public Lecture: Transport and fate of DDT on the Palos Verdes shelf, CA: a source-to-sink story; Technical Lecture: Formation and pres-ervation of event-scale stratigraphy in the coastal ocean.

David MohrigDavid is an Associate Professor in the

Department of Geological Sciences at the University of Texas at Austin.Public Lecture: Application of Earth Sci-

ence and Engineering to Maintenance ofthe Mississippi River Delta; Technical Lecture: Comparing the Evolu-tions of Lowland Rivers and SubmarineChannels.

Rupturing Continental Lithosphere John Hopper

John is an Assistant Professor of Geol-ogy and Geophysics at Texas A&M Uni-versity.Public Lecture: Massive volcanism during Earth’s history from breaking continents apart; Technical lecture: The Newfoundland-Iberia Rift System: Insights into crust and mantle processes of breakup and early seafloor spreading.

Donna Shillington Donna is a Doherty Associate Research

Scientist at Lamont-Doherty Earth Obser-vatory.Public Lecture: Recipe(s) for continental breakup; Technical lecture: An abrupt along-strike transition from magma-poor to magma-rich rifting in the eastern Black Sea.

Interested in hosting a speaker?

Any college or university wishing to invite a MARGINS speaker may apply via the MARGINS Office web-site: www.nsf-margins.org/DLProgram. Applications are due July 15, 2008. Invitations from institutions that are not currently involved with MARGINS research are strongly encouraged to apply, including those granting undergraduate or masters degrees, as well as those with Ph.D. programs. Institutions may request a technical and/or public lecture.

The MARGINS Office will cover airfares for speakers’ travel and will coordinate travel and off-site logistics. Host institutions are responsible for local expenses for the duration of the visit.

The MARGINS Speakers and Lecture Themes

Year 2008-2009

The MARGINS Office announces the fourth annual MARGINS Distinguished Lectureship Program for academic year 2008- 2009 with an outstanding line-up of speakers.

Distinguished scientists involved with MARGINS science and planning are available to visit American colleges and universities to present technical talks and public lectures on subjects related to the four MARGINS science initiatives (www.nsf-margins.org).Speakers from last year extend their tour.

The MARGINS Office is glad to announce that speakers from the 2007-2008 lectureship program have graciously accepted to participate in another round of lecture series for the current program. Farewell and thanks to Casey Moore, Daniel Lizarralde, Karen Fischer, and Charles Nittrouer for their past two years of contribution to the lectureship program!

MARGINS Newsletter No. 20, Spring 2008 Page 23MARGINS Lectures

Biographies of MARGINS New DLP Speakers (www.nsf-margins.org/DLProgram/)

Tim Dixon uses space geodetic techniques such as GPS and InSAR (Interferometric Synthetic Aperture Radar) to study motion and deformation of Earth’s surface due to faulting, earthquakes, volcanic activity and coastal subsidence.

Simon Klemperer uses seismic methods to image lithospheric structure, and to understand the growth, composition and tectonic evolution of continental crust. His research emphasises acquisition of new datasets to explore “natural laboratories”: key regions of earth that exemplify important active processes. A key “Subduction Factory” experiment within the MARGINS initiative has been to measure the crustal volumes and compositions created above the intra-oceanic Mariana subduction zone. Other recent foci of Klemperer’s research in continental tectonics have been Tibet and the Himalaya, the East African Rift, and the Basin-and-Range province of western North America.

David Mohrig’s research group focuses on the application of sedimentary deposits and transport processes to unraveling the evolutions of submarine and terrestrial landscapes. The group studies the behavior of topography generated at the inter-face between a granular material and a fluid from very short to very long time and space scales, with particular emphasis on processes controlling channel formation, both on land and in the deep ocean. Research methods used by his group include carefully designed laboratory and natural experiments on sediment-transporting flows, field studies of modern and ancient sediment-dispersal systems, theoretical modeling of evolving granular-bed topography, and the remote sensing of subsurface sedimentary deposits (interpretation and visualization of seismic data).

Donna Shillington examines the processes associated with continental rupture and initial seafloor spreading using seismic reflection and refraction data in combination with other geophysical/geological data and quantitative techniques, such as subsidence analysis. She has studied these processes at extensional systems such as the Newfoundland-Iberia conjugate margins and the Black Sea. She is also interested in magmatic processes in island arcs and in characterizing variations in pore-pressure and pore-fluid content in sediments.

Biographies of MARGINS Continuing Speakers

Greg Hirth investigates processes that control the rheological behavior of the Earth’s crust and upper mantle. He studies problems ranging from brittle deformation of the shallow lithosphere to viscous flow of the asthenosphere. While emphasizing an experimental approach, he also collaborates with field geologists and geophysicists to explore the implications of rheological data for the mechanical behavior of the Earth, and to constrain the strengths and limitations of laboratory measurements. John Hopper: How and why continents breakup apart to form new ocean basins is the cornerstone of John’s research. He uses seismic imaging methods and numerical modeling to understand the crustal and lithospheric structure of different tectonic settings to better understand the dynamic processes associated with how different regions evolve. He has studied rift processes in the North Atlantic around Greenland and Iceland, Newfoundland and Iberia, as well as NW Australia. Most recently, he has become involved in projects to unravel the tectonic history of Arctic Ocean basins.

Peter Kelemen: In subduction research, Peter focuses on the origin of continental crust, including genesis of primitive andesites, foundering of dense lower crust, thermal structure of subduction zones, intermediate depth earthquakes, cratonic upper mantle, and ultra-high pressure metamorphic rocks. Initially specializing in “extreme terrain mineral exploration”, he also studies mid-ocean ridge melt transport and crust formation, and carbon sequestration via peridotite weathering. He has worked in India, Pakistan, Greenland, Peru, Alaska, B.C., Oman, the Bering Sea, the Atlantic Ocean, and the continental US.

Patricia Wiberg’s research focuses on the role of sediment bed properties in controlling sediment transport and morphologic evolution, primarily in shallow marine environments. Her work spans a range of temporal and spatial scales from the motion of individual sediment grains to the evolution of continental margin morphology. A particular interest is the potential for preservation of flood and storm event beds in the longer-term stratigraphic record.

Page 24 MARGINS Newsletter No. 20, Spring 2008

Bilek, S.L., 2007, Influence of subduct-ing topography on earthquake rupture, In T. Dixon and J.C. Moore eds., The Seismogenic Zone of Subduction Thrust Faults, Columbia Univ. Press New York, p 123-146.

Brown, K.M., Kopf, A., Underwood, M.B., and Weinberger, J.L., 2003, Composi-tional and fluid pressure controls on the state of stress on the Nankai subduction thrust: A weak plate boundary, Earth Planet. Sci. Lett., 214, 589-603.

Brown, K. M., M. D. Tryon, H. R. DeShon, L. M. Dorman, and S. Y. Schwartz, 2005, Correlated transient fluid pulsing and seismic tremor in the Costa Rica subduc-tion zone, Earth Planet. Sci. Lett., 238, 189–203.

Cutillo, P.A., S. Ge, and E. Screaton, 2006, Hydrodynamic response of subduction zones to seismic activity: A case study for the Costa Rica Margin, Tectonophysics, 426, 167-187.

Davis, E. E., K. Becker, K. Wang, K. Obara, Y. Ito, and M. Kinoshita, 2006, A discrete episode of seismic and aseismic defor-mation of the Nankai trough subduction zone accretionary prism and incoming Philippine Sea plate, Earth Planet. Sci. Lett., 242, 73–84.

DeShon, H.R., Schwartz, S.Y., Newman, A.V., Gonzalez, V., Protti, M., Dorman, L.M., Dixon, T.H., Sampson, D.E., Flueh, E.R., 2006, Seismogenic zone structure beneath the Nicoya Peninsula, Costa Rica, from three-dimensional local earthquake P- and S-wave tomography,

SEIZE references (continued from pg 6): Geophys. J. Int., 164, 109-124.Dixon, T.H., and Moore, J.C. (eds), 2007, The

Seismogenic Zone of Subduction Thrust Faults, Columbia Univ. Press, New York, 680 pp.

Dragert, H., Wang, K., and James, T.S., 2001, A silent slip event on the deeper Cascadia subduction interface, Science, 292, 1525-1528.

Gamage, K., and E. Screaton, 2006, Charac-terization of excess pore pressures at the toe of the Nankai accretionary complex, Ocean Drilling Program sites 1173, 1174, and 808: Results of one-dimensional modeling, J. Geophys. Res., 111, B04103, doi:10.1029/2004JB003572.

Ge. S., and Screaton, E., 2005, Modeling seismically induced deformation and fluid flow in the Nankai subduction zone, Geophys. Res. Lett., 32, L17301, doi:10.1029/2005GL023473.

Ghosh, A., A.V. Newman, A.M. Thomas, and G.T. Farmer, 2008, Interface locking along the subduction megathrust from b-value mapping near Nicoya Peninsula, Costa Rica., Geophys. Res. Lett., 35., L01301, doi:10.1029/2007GL031617.

Goldfinger, C., Nelson, C.H., Johnson, J.E., Erickson, D., Winkler, M., Kalk, P., Pas-tor, J., Camarero, A., Morri, C., Dunhill, G., Ramos, L., Raab, A., Pisias, N., Ppur-manoutscheri, M., van Rooij, D., Amy, L., Liu, C.C., 2003, Holocene earthquake re-cords from the Cascadia subduction zone and northern San Andreas Fault based on precise dating of offshore turbidites, Ann. Rev. Earth Planet. Sci., 31, 555-577.

Harris, R.N., and Wang, K., 2002, Ther-mal models of the Middle America trench at the Nicoya Peninsula, Costa

Rica, Geophys. Res. Lett., 29, doi: 10.1029/2002GL015406.

Heki, K., 2007, Secular, transient, and sea-sonal crustal movements in Japan from a dense GPS array, In T. Dixon and J.C. Moore eds., The Seismogenic Zone of Subduction Thrust Faults, Columbia Univ. Press, New York, 512-539.

Hyndman, R.D., 2007, The seismogenic zone of subduction thrust faults: What we know and don’t know, In T. Dixon and J.C. Moore eds., The Seismogenic Zone of Subduction Thrust Faults, Columbia Univ. Press, New York, 15-40.

Hyndman, R. D., and K. Wang, 1993, Ther-mal constraints on the zone of major thrust earthquake failure: The Cascadia subduction zone, J. Geophys. Res., 98, 2039–2060.

Ide, S., Beroza, G.C., D.R. Shelly, and T. Uchide, A scaling law for slow earth-quakes, Nature, 447, 76-79, 2007.

Ito, Y., and Obara, K., 2006. Very low frequen-cy earthquakes within accretionary prisms are very low stress-drop earthquakes. Geophys. Res. Lett., 33(9):L09302. doi:10.1029/2006GL025883.

Kimura, G., Screaton, E.J., Curewitz, D., and the Expedition 316 Scientists, 2008. NanTroSEIZE Stage 1A: NanTroSEIZE shallow megasplay and frontal thrusts. IODP Prel. Rept., 316. doi:10.2204/iodp.pr.316.2008.

Kinoshita, M., Tobin, H., Moe, K.T., and the Expedition 314 Scientists, 2008. NanTroSEIZE Stage 1A: NanTroSEIZE LWD transect. IODP Prel. Rept., 314. doi:10.2204/iodp.pr.314.2008.

Kodaira, S., Iidaka, T., Kato, A., Park, J.-O., Iwasaki, T., Kaneda, Y., 2004, High pore fluid pressure may cause silent slip in the Nankai Trough, Science, 304, 1295-1298.

MARGINS Science Plan, 2004 Marshall, J.S., LaFromboise, E.J., Gardner,

T.W., and Protti, M., 2007, Segmented forearc deformation along the Nicoya Peninsula seismic gap, Costa Rica, Eos Trans. AGU, 8(52), Fall Meet. Suppl., Abstract T53A-1121.

McIntosh, K.D., Silver, E.A., Ahmed, I., Berhorst, A., Ranero, C.R., Kelly, R.K., and Flueh, E.R., 2007, The Nicaragua Convergent Margin, In T. Dixon and J.C. Moore eds., The Seismogenic Zone of Subduction Thrust Faults, Columbia Univ. Press, New York, 257-287.

Marone, C., and Saffer, D., 2007, Fault fric-tion and the upper transition from seismic

MARGINS Bibliography

The MARGINS Office has compiled a list of publications that have resulted from or strongly influenced MARGINS-funded programs. View the bibliogra-phy and download the list as a searchable EndNote™ library!

www.nsf-margins.org/Bibliography

The bibliography page is also linked from the MARGINS web page.

The bibliography includes fields for NSF-MARGINS award number, focus site, initiative – download the library to sort on these fields.

Wait – my paper’s not there! Oops - contact the MARGINS Office and we’ll update the list!

MARGINS Newsletter No. 20, Spring 2008 Page 25

to aseismic faulting, In T. Dixon and J.C. Moore eds., The Seismogenic Zone of Subduction Thrust Faults, Columbia Univ. Press, New York, 346-369.

Moore, D.E., and Lockner, D.A., 2007, Fric-tion of the smectite clay montmorillonite, In T. Dixon and J.C. Moore eds., The Seismogenic Zone of Subduction Thrust Faults, Columbia Univ. Press, New York, 317-345.

Moore, G. F., N. L. Bangs, A. Taira, S. Kura-moto, E. Pangborn, and H. J. Tobin, 2007, Three-dimensional splay fault geometry and implications for tsunami generation, Science 318 (5853), 1128. [DOI: 10.1126/science.1147195].

Moore, J.C., Rowe, C., and Meneghini, F., 2007, How can accretionary prisms eluci-date seismogenesis in subduction zones? In T. Dixon and J.C. Moore eds., The Seismogenic Zone of Subduction Thrust Faults, Columbia Univ. Press, New York, 288-315.

Moore, J.C. and D. Saffer, 2001, Updip limit of the seismogenic zone beneath the ac-cretionary prism of southwest Japan: An effect of diagenetic to low-grade meta-morphic processes and increasing effec-tive stress, Geology, 29, 183-186.

Morgan, J.K., E.B. Sunderland, M.V.S. Ask, 2007, Deformation and mechani-cal strength of sediments at the Nankai subduction zone: Implications for prism evolution and décollement initiation and propagation, In T. Dixon and J.C. Moore eds., The Seismogenic Zone of Subduction Thrust Faults, Columbia Univ. Press, New York, 210-256.

Norabuena, E., et al., 2004, Geodetic and seismic constraints on some seis-mogenic zone processes in Costa Rica, J. Geophys. Res., 109, B11403, doi:10.1029/2003JB002931.

Obara, K., 2002, Nonvolcanic deep tremor associated with subduction in southwest Japan, Science, 296(5573), 1679–1681.

Psencik, K.C., Jiang, Y., LaFemina, P.C., Dixon, T.H., Protti, M., Gonzales, V., Sklar, J., Blume, F., 2007, Current status and future directives of the Nicoya Pen-insula continuous GPS network, Costa Rica, in regard to slip style and distribu-tion, Eos Trans. AGU, 8(52), Fall Meet. Suppl., Abstract G23A-04.

Protti, M., F. Güendel, and K. McNally , 1995, Correlation between the age of the subducting Cocos plate and the geom-etry of the Wadati-Benioff zone under Nicaragua and Costa Rica, in Geologic

and Tectonic Development of the Carib-bean Plate Boundary in Southern Central America, edited by P. Mann, Spec. Pap. Geol. Soc. Am., 295, 309 – 326.

Richardson, E., and Marone, C., 2008, What triggers tremor? Science, 319, 166-167.

Rogers, G. C., and H. Dragert 2003, Episodic tremor and slip on the Cascadia subduc-tion zone: The chatter of silent slip, Sci-ence, 300(5627), 1942–1943.

Rowe, C.D., J. C. Moore, F. Meneghini, and A. W. McKeirnan, 2005, Large-scale pseudotachylytes and fluidized catacla-sites from an ancient subduction thrust fault, Geology, 33(12):937-940.

Saffer, D.M., and C. Marone, 2003, Com-parison of smectite- and illite-rich gouge frictional properties: Applicaton to the updip limit of the seismogenic zone along subduction megathrusts, Earth Planet. Sci. Lett., 215, 219-235.

Saffer, D.M., 2003, Pore pressure develop-ment and progressive dewatering in underthrust sediments at the Costa Rican subduction margin; comparison with northern Barbados and Nankai, Geophys. Res., 108, (BS), art. no. 2261.

Saffer, D.M., 2007, Pore pressure within underthrust sediment in subduction zones, In T. Dixon and J.C. Moore eds., The Seismogenic Zone of Subduction Thrust Faults, Columbia Univ. Press, New York, 171-209.

Scholz, C., 1998, Earthquakes and friction laws, Nature, 391, 37-42.

Schwartz, S.Y., and DeShon, H.R., 2007, Distinct updip limits to geodetic locking and microseismicity at the northern Costa Rica seismogenic zone, In T. Dixon and J.C. Moore eds., The Seismogenic Zone of Subduction Thrust Faults, Columbia Univ. Press, New York, 576-599.

Schwartz, S. Y., and J. M. Rokosky 2007, Slow slip events and seismic tremor at circum-Pacific subduction zones, Rev. Geophys., 45, RG3004, doi:10.1029/2006RG000208.

Screaton, E., Saffer, D., Henry, P., Hunze, S., and the Leg 190 Scientific Party, 2002, Porosity loss within the underthrust sediments of the Nankai accretionary complex: Implications for overpressures, Geology, 30, 19–22.

Screaton, E.J. and S. Ge, 2007, Modeling of the effects of propagating thrust slip on pore pressures and implications for monitoring, Earth Planet. Sci. Lett., 258, 454-464.

Silver E., Plank, T., and van Keken, P., 2007,

Workshop to integrate subduction factory and seismogenic zone studies in Central America, Heredia, Costa Rica, June 18-22, 2007, MARGINS Newsletter #19.

Spinelli, G., and D. M. Saffer, 2004, Along-strike varations in underthrust sediment dewatering on the Nicoya margin, Costa Rica, related to the updip limit of seis-micity, Geophys. Res. Lett., 31, L04613, doi:10.1029/2003GL018863.

Spinelli, G.A., and Saffer, D.M., 2007, Trench-parallel fluid flow in subduction zones resulting from temperature differ-ences, Geochem. Geophys. Geosyst., 8, doi:10.1029/2007GC001673.

Spinelli, G.A., and Underwood, M.B., 2005, Modeling thermal history of subduct-ing crust in Nankai Trough; constraints from in situ sediment temperature and diagenetic reaction progress, Geophys. Res. Lett., 32.

Spinelli, G.A., Mozley, P.S., Tobin, H.J., Underwood, M.B., Hoffman, N.W., and Bellew, G.M., 2007, Diagenesis, sediment strength, and pore collapse in sediment approaching the Nankai Trough subduc-tion zone, GSA Bull., 119, 377-390.

Tobin, H.J., and Kinoshita, M., 2006, NanT-roSEIZE: the IODP Nankai Trough Seis-mogenic Zone Experiment. Sci. Drill., 2:23–27. doi:10.2204/iodp.sd.2.06.2006

Tobin, H, D. Saffer, P. Costa-Pisani, and G. Moore, 2005, Spatial Distribution of Pore Pressure and Effective Stress at the Western Nankai Trough Plate Interface Based on 3D Seismic Reflection Data, Eos Trans. AGU, 87(52), Fall Meet. Suppl., Abstract T12C-06.

Trehu, A.M., Braunmiller, J., and Nabalek, J.L., 2008, Probable low-angle thrust earthquakes on the Jaun de Fuca – North American plate boundary, Geology, 36, 127-130.

Underwood, M.B., 2007, Sediment inputs to subduction zones, In T. Dixon and J.C. Moore eds., The Seismogenic Zone of Subduction Thrust Faults, Columbia Univ. Press, New York, 42-85.

Wells, R.E., Blakely, R.J., Sugiyama, Y., Scholl, D.W., and Dinterman, P.A., 2003, Basin centered asperities in great subduction zone earthquakes: a link between slip, subsidence, and subduc-tion erosion, J. Geophys. Res., 108, doi:10.1029/2002JB002072.

Page 26 MARGINS Newsletter No. 20, Spring 2008

NSF Awards 0738723 and 0739017Collaborative Research: Testing the Role of Transtension in Continental Rupture: An Integrative Study of the Sonoran Margin and Tiburón Basin, Northern Gulf of California Rebecca Dorsey1, Michael Oskin2

1University of Oregon, Eugene; 2University of North Carolina at Chapel Hill Cofunded by MARGINS and Tectonic Programs: Development of strain parti-tioning in transtensional rifts may play a significant role in localizing continental rupture. Partitioning of extension and dex-tral shear in the proto-Gulf of California during Late Miocene time (12 to 6 million years ago) remains a fundamental unre-solved problem that hinders understanding of the initial conditions for ocean basin formation. Preliminary evidence from coastal Sonora is supportive of a regional model that promotes dextral transtension in a zone of uncertain width prior to localiza-tion of plate-boundary motion in the Gulf of California approximately 6 million years ago. It is not known whether Late Miocene dextral shear was sufficiently fast or fo-cused to alter rheological conditions and change the mode of rifting from distributed Basin-and-Range-style extension to local-ized lithospheric necking, subsidence, and continental rupture. In this project U.S. and Mexican scientists aim to constrain the structural distribution of dextral shear over time during localization of the plate boundary. Specifically, they will determine whether late Miocene transtension in the proto-Gulf of California was accommo-dated by diffuse 3-dimensional strain in a wide zone of coeval strike-slip and normal faults or occurred in a narrow zone of dis-crete dextral faults and/or rotating blocks embedded within a broader zone of East-West extension. To discriminate between these models, the team is investigating the geologic structure and basin development of the Sonoran continental margin, includ-ing adjacent Isla Tiburon and the offshore Sonora shelf by: (1) documenting the dis-tribution of dextral shear through detailed

structural mapping and paleomagnetic analysis; (2) quantifying transtensional strain rates using structural reconstructions, 40Ar/39Ar dating of intercalated volcanic rocks, and subsidence analysis of syntec-tonic sedimentary and volcanic basins; and (3) integrating the onshore geologic record with offshore structures and basins by inter-pretation of existing multi-channel seismic data from the offshore Tiburon basin. The Gulf of California provides an excellent natural laboratory for studying processes of continental break-up. Previous studies have shown that warm continental crust tends to resist localized deformation, which is required for rupture of continental litho-sphere. Data from this study will improve understanding of how and why the warm crust of western North America ruptured to form the Gulf of California, which has been opening since about 6 million years ago. This project is supported by the EAR Tectonics Program, the NSF Office of in-ternational Science and Engineering, and the NSF/OCE MARGINS program. The research involves significant participation of graduate and undergraduate students, collaboration with Native Americans, and strong international partnerships with re-search institutions in Mexico.

NSF Award 0742242 MARGINS FELLOWSHIP: The effect of frictional properties in subduction zones on earthquake trig-gerability Emily BrodskyUniversity of California, Santa Cruz This is a MARGINS post-doctoral fellow-ship project. The post-doc will investigate how fault zone thicknesses affects large-scale fault stability at subduction zones. The specific tasks to be accomplished are: 1. Assessment of aftershock productivity on the Northern Costa Rican, Southern Costa Rican, and Nankai subduction zones to establish stability differences between subduction zones with varying frictional

NSF Awards

MARGINS-NSF Awards 2008These are the funded MARGINS Proposals for the fiscal year 2008. If and when additional awards with-in the MARGINS Program are announced we will add the details to the MARGINS Awards web page <www.nsf-margins.org/Mawards.html>.

properties. 2. Investigation of the potential for remote triggering at the Costa Rican margin through high pass filtering of large earthquake waveforms. 3. Development of analytical models showing the relation-ships between fault gouge thickness, force chains, asperity contact and the critical slip distance over which a fault weakens enough to fail dynamically. This is an ambi-tious project for two years, but if successful will help us understand how strain builds in various subduction settings, and how fre-quently the strain must be relieved as well as how such events can be triggered. The potential broader impacts of this project include the benefit to society with respect to improving our understanding of earth-quake triggering as well as the training of a promising young female researcher.

NSF Award 0742263Collaborative Research: Seismic Im-aging of New Transitional Crust in the Salton Trough Oblique RiftJohn Hole1, Joann Stock2, Gary Fuis3

1Virginia Tech ; 2Caltech; 3USGS Menlo ParkCo-funded by the NSF MARGINS Pro-gram, the NSF EarthScope Program, and the U.S. Geological SurveyIntellectual Merit: This project addresses the processes of rupturing a continent through an onshore seismic refraction and reflection survey at the Salton Trough, the northernmost part of the Gulf of California extensional province. The southern and central Gulf were the target of a recent MARGINS project, and significant dif-ferences in rifted continental margins were observed in adjacent rift segments. Seismic refraction and reflection studies in the northern Gulf indicate that stretched continental crust still underlies the rift. In the Salton Trough, however, the 20-22 km thick crust is composed entirely of new material added by magmatism from below and Colorado River sedimentation from above. Our scientific goals are to investi-

MARGINS Newsletter No. 20, Spring 2008 Page 27

gate: i) the nature of transitional crust at rifted continental margins, ii) the role and mode of magmatism in the final stages of continental breakup, iii) the effect of rapid syn-rift sedimentation on magmatism and extension mechanism, iv) the partition-ing of displacement in highly oblique continental rifting, and v) 3-D structure for earthquake hazards evaluation. These targets will be constrained by densely sampled seismic refraction/wide-angle reflection and by seismic reflection imag-ing of the crust and upper mantle in and across the Imperial and Coachella Valleys.We encourage and invite potential col-laborations. Since seismic data acquisi-tion is currently scheduled for December 2009 - January 2010, there is time to submit a grant proposal for piggyback field operations. Project web site: http://www.geophys.geos.vt.edu/hole/salton/

NSF Awards 0742282 and 0742490MARGINS: Col laborative Re -search: Modeling 3-D Wedge Flow with Complex Slab Geometries and Comparisons with Seismic Anisot-ropyKaren Fischer1, Christopher Kincaid2 1Brown University; 2University of Rhode Island In 2002 the NSF MARGINS program funded a project to develop a laboratory

apparatus for modeling three-dimensional (3-D) aspects of circulation and heat/mass transport in subduction zones. Using this apparatus Chris Kincaid (URI) and Ross Griffiths (ANU) have modeled the 4-D evo-lution of the mantle wedge and subducting slab for cases with relatively simple plate forcing scenarios (rollback motion, back-arc spreading) and plate geometries. A new MARGINS effort (PIs: Chris Kincaid and Karen Fischer builds upon this prior work by integrating the 3D laboratory models with insight on slab, mantle wedge, and upper plate properties gained from seis-mic imaging experiments in MARGINS Subduction Factory focus areas (Nicara-gua-Costa Rica and the Marianas). In one set of experiments we will investigate the relationship between the flow and thermal response of subduction systems and com-plex slab morphology. For example, mod-els will define how 3D flow in the mantle wedge responds to along-arc variations in slab dip, slab roll-back and slab integrity (e.g., tears) and along-arc components of upper plate deformation. Another series of models will investigate the interaction between wedge material with anomalous viscosity and/or buoyancy and 3-D wedge shear flows driven by slabs exhibiting such a range in morphology and plate motion history. Flow fields in these models will be tested against shear-wave splitting obser-vations and models of seismic anisotropy from around the globe, with a particular focus on Nicaragua-Costa Rica and the

Marianas where significant anisotropy with an arc-parallel fast symmetry axis has been observed. For example, when more complex features of plate forcing are included in 3-D models, are they sufficient to produce spatial patterns of anisotropy consistent with observations? If flow-in-duced anisotropy fails to match the obser-vations, what alternative hypotheses need to be explored (e.g., different dominant slip system, aligned melt sheets)? How do geometric and kinematic complexities in plate forcing interact with altered or chemically distinct regions of the mantle wedge? How do these interactions influ-ence patterns in vertical flow within the wedge, including melt transport? Results will highlight the aspects of wedge melt-ing models that need to be re-evaluated in light of subduction-driven 3-D wedge flow.

NSF Award 0742288Geochemical Core Logging of Gulf of Papua Sediments for Source-to-Sink StudiesLarry Peterson Princeton UniversityC o - f u n d e d b y t h e N S F M A R -GINS Program, the NSF EarthScope Program, and the U.S. Geological Survey. New core logging technology now makes it possible to acquire high resolution geochemical data at a rate and sampling interval impossible using conventional methods. This project will make use of X-Ray Fluorescence (XRF) core scan-ning to geochemically characterize the large set of sediment cores previously acquired during our 2004 field program in the deeper offshore portion of the Gulf of Papua New Guinea (PNG). XRF core scanning is ideally suited for Source-to-Sink sediment studies because the wide range of measurable elements can be used to better identify and constrain sediment provenance and hence lead to a more ac-curate accounting of source end-members and their variability through time. Mixed carbonate-siliciclastic systems like the Gulf of PNG are relatively common in the geo-logical record and thus constitute important archives of Earth history. Our ultimate intellectual objective is to develop a more realistic model for mixed system sedimen-

MARGINS Databasewww.marine-geo.org/margins

Download data! Get field program information!

Visit the MARGINS database to find information on over sixty MARGINS-funded and related terrestrial and marine field programs in the six Focus Sites.

Data Link (www.marine-geo.org/link/index.php) – search for data and information by keyword such as investigator, Focus Site, data type, cruise ID.

GeoMapApp (www.geopmapapp.org) – explore and visualize data. Import grids, spreadsheets, and shape files. Create custom maps and grids. Export grids, images, and

data. Connect seamlessly to partner databases including PetDB, SedDB, UNAVCO, IRIS, NGDC.

Link to MARGINS mini-lessons and education modules.

The MARGINS database is a free community resource. For more information about the MARGINS database, please contact info@marine-geo.org or the MARGINS Office.

Page 28 MARGINS Newsletter No. 20, Spring 2008

tation and to understand how variations in sediment processes and fluxes combine with longer-term variations in climate and sea level to build a stratigraphic record.

NSF Awards 0742460 and 0742458MARGINS: Collaborative Research: Origins of Local Variations in Subduc-tion-Related Fluids: Evidence from Ol-ivine-Hosted Melt Inclusions from the Central American Subduction Zone Kurt Roggensack1 , James Walker2

1Arizona State University; 2Northern Illinois UniversityIntellectual Merit: One of the most im-portant processes that occurs at subduc-tion zones is the fluid-mediated transfer of material from subducting lithosphere into overlying mantle. The sources of fluid for this important mass transfer remain controversial. Along the Central American subduction zone erupted basaltic magmas display systematic geochemical varia-tions along the volcanic front which have been linked to changes in intensity and the agents of slab-to-wedge mass transfer. In the Nicaraguan portion of the Central American subduction zone there are also local (i.e., intravolcano) geochemical variations in basaltic magmatism that can rival the much-ballyhooed along-arc differences. These local variations in the chemistry of erupted basalts have also been linked to variations in fluid transfer from the subducting Cocos plate. They may also reflect local variability in melt generation and/or mantle wedge depletion. We pro-pose to critically evaluate the origin of the local geochemical variations in Nicaragua through major, volatile and trace element analyses of olivine-hosted melt inclusions in basaltic tephras. A full major, volatile and trace element characterization of the melt inclusion popu-lation in Nicaraguan basaltic tephras will allow us to determine the range in primitive compositions feeding Nicaraguan volca-noes. We can then test whether the range in primitive compositions is caused by local variations in fluid input from the subducting Cocos plate; in the melting history of the mantle wedge; or in the melting dynamics in the mantle wedge. The volatile and trace element contents of the melt inclusions

will also permit further characterization of the slab signals imprinted on Nicaraguan magmas and, when combined with exist-ing whole-rock data, help us to identify the fluid bearers of these slab signals, a ques-tion that remains unresolved both on local and regional scales. Better constraints on the variety of slab-related fluids contribut-ing to magmatism are integral to identify-ing which tectonic parameters (slab dip, slab hydration, crustal thickness) are most instrumental in creating an environment conducive to maximizing heterogeneity in erupted magma compositions in Nica-ragua and along other subduction zones. The volatile element analyses of the melt inclusions will include the determinations of H2O, CO2, Cl and S. This will allow us to evaluate all of the magmatic processes that can affect the volatile concentrations of magmas. Thus, we will be able to determine the degassing histories of magmas at indi-vidual volcanoes, which exerts a critical control on the explosivity of eruption.Broader Impacts: The proposed project will provide continued support for pro-grams at both Northern Illinois University and Arizona State University involving research experience for undergraduate students, particularly female students. In addition, it will permit continued trans-fer of scientific knowledge to Central American colleagues to help enhance community-level understanding about the workings of active and dormant volcanoes. For instance, knowledge of the degas-sing and eruptive processes learned from melt inclusions will provide important information on potential volcanic hazards.

NSF Award 0742526Collaborative Research:Geomor-phodynamic Modulation of Bio-g e o c h e m i c a l F l u x e s a n d B a -sin Stratigraphy of the Fly River

Miguel Goni1, Rolf Aalto2, Bill Dietrich3, Anthony Aufdenkampe4

1Oregon State University; 2Exeter Univer-sity; 3University of California, Berkely; 4Stroud Water Research Center Our multidisciplinary team proposes coor-dinated field and laboratory investigations and synthesis modeling to investigate the processes responsible for the transport and sequestration of organic carbon by the Fly River and associated floodplain, which we expect are globally significant. We will specifically investigate the role that sediment exchange processes between channels and floodplains play in modulat-ing biogeochemical fluxes, including the composition, source, age and stability of organic matter. Additionally, we will study how partial and full channel avulsions govern sediment and carbon accumulation across the distal floodplain and hence the infill of these lowland alluvial basins. To explore these processes, we propose to (1) quantify the character, concentration, and fluxes of organic matter and biogeo-chemically reactive particles, with a focus on variability with discharge and source; (2) document migration rates and cross-meander-apex profiles of topography and biogeochemical properties; and (3) survey and core the distal floodplain at several reaches where early avulsion processes appear to be delivering large quantities of sediment and burying organic rich flood-basins to determine the rates and character of aggradation. We will combine these field surveys of sediment/biogeochemical; transport and depositional processes with numerical modeling, image analysis, and monitoring at established gauging stations to determine (i) the fluxes, exchanges, and sinks for fine particles, and (ii) the related fluxes and net changes in the quantities, characteristics, and turnover times of as-sociated organic carbon. This research will provide critical insight into the strength,

NSF Awards

Not receiving MARGINS email announcements?It’s easy to update your e-mail address and other contact information. Fill in

the simple web form at www.nsf-margins.org/MailingUpdateForm.html

MARGINS E-mail Announcements

MARGINS Newsletter No. 20, Spring 2008 Page 29

timing, and controls on the “source” term for water, sediment, and biogeochemical fluxes within this NSF Margins Source-to-Sink study area, enhancing prior research conducted downstream. Our findings could have strong implications for greenhouse gas and climate change issues, and also for the stability, morphodynamics, and buffer-ing of water, particle, and carbon fluxes by lowland river floodplains – areas that also provide prime habitats and fertile agricul-tural land and are geologically important as depocenters for sedimentary strata.

NSF Awards 0742368 and 0742451Collaborative Research: Element Recycling from UHP Metasediments: Evidence and Consequences

Peter Kelemen1, Bradley Hacker2

1Columbia University; 2University of Cali-fornia-Santa BarbaraThis is a study of ultra-high-pressure (UHP) metasediments that have been subducted to >75 km, to quantify element recycling processes during dehydration and/or melt extraction at volcanic arcs. The aim of the research is to understand the fluxes of mate-rial into and out of subduction zones and volcanic arcs. In turn, this is fundamental to understanding global geochemistry, and is a central goal of the MARGINS Initiative. This research on UHP metasedimentary samples will collect new data for major- and trace-element and isotope exchange thermometers. Trace elements in selected metasediments will be compared to those in normal fine-grained sedimentary rocks to identify systematic changes associated with melt extraction or dehydration. The results should provide constraints on the budget of key elements in subducting metasediments, and the extraction of these elements via fluid and melt transport into the zone of magma genesis beneath arcs. Broader impacts include training of two graduate students, presentation of results in papers and talks, archiving of data in the SedDB global sedimentary rock data base, and extensive, ongoing outreach efforts via web and informal lectures by the PI’s.

NSF Award 0751600Cenozoic crustal genesis in SW Pacific arcs and backarcs James GillUniversity of California, Santa Cruz Intellectual Merit: This research ex-amines how the mantle and crust of the Earth evolve from during one ~50 million year cycle of subduction, from initiation to demise, in the absence of pre-existing continental crust. It involves three igneous petrological projects on rocks from the Ker-madec-Fiji-Tonga area of the SW Pacific. Test 5 using the geochemical and isotopic signatures of volcanic rocks will be used to answer (1) whether subduction initiation has a characteristic magmatic signature and cause; (2) if magma genesis in the mantle wedge during back-arc rifting evolves from flux-dominated to decompression-domi-nated melting; and (3) whether geochemi-cal features of primary arc magmatism get passed on to “second stage” crust that is continental in character. The geochemical plan includes generation and interpretation of extensive trace element and Nd-Hf-Sr-Pb isotope data. In addition, U/Pb and

Ar-Ar ages will be obtained for igneous rocks, and results compared to analogues in the northern hemisphere. The first project focuses on the oldest rocks in Fiji and Tonga. The second focuses on basalts erupted in Fiji during 3-5 Ma, and those in cross-chains and rift basins in the Havre Trough. The third uses the granitic plutons of different ages and compositions in Fiji and includes (U-Th)/He “double-dating”. One anticipated impact will be to assess the commonality of processes between Earth’s two largest and best-studied oceanic arcs: Izu-Marianas, and Kermadec-Fiji-Tonga.Broader Impacts: All three projects di-rectly complement the NSF-funded island arc and backarc basin research foci in Ridge 2000, MARGINS, and IODP. They also involve international collaboration with scientists in Japan and New Zealand. The project provides education/training op-portunities for two graduate students and several undergraduates. Public outreach and dissemination will occur through the MARGINS Education and Outreach program and a well-documented sample collection will be provided to the Smithso-nian National Museum of Natural History “Islands” collection where it will be curated indefinitely.

In January 2008 the MARGINS Office moved from Boston University to the Lamont-Doherty Earth Observatory of Columbia University. Geoffrey Ab-ers continues to lead the program and has gained two new members for the MARGINS Office.

Niva Ranjeet (Co-ordinator) received a B.S. in Geophysics from the University of Connecticut and a Master’s in Phys-

ics from California State University, Northridge. Beyond MARGINS re-sponsibilities, Niva is active in sev-eral community outreach groups and NGO’s such as the Nepali Women’s

Global Network (NWGN), Association of Nepali Americans (ANA), and Captive Daughters (CD).

Andrew Goodwillie followed a D.Phil. in marine geophys-ics/geodynamics from the Univer-sity of Oxford, by working on lithospheric flex-ure problems at

Scripps Institution of Oceanography and in the Scripps Geological Data Centre. In addition to duties in the MARGINS database group at LDEO, Andrew now helps in the MARGINS Office. He is a registered yoga teacher, and enjoys hik-ing in mountains and travelling widely.

The MARGINS Office has Moved!

Page 30 MARGINS Newsletter No. 20, Spring 2008

MARGINS Data in the classroom: Mini-LessonsDid you know that more than a dozen mini-lessons are available for you to use in undergraduate teaching?

The MARGINS mini-lessons focus upon aspects of MARGINS science, from general concepts to detai-led analysis and highlight the MARGINS database and database resources including GeoMapApp and PetDB. Here’s a small selection of MARGINS mini-lessons:

Are You in a Hotspot?

Where is California Going?

Physical and Chemical Variations Along the Central American Volcanic Arc

Connecting Cross-Sectional Data from the Red Sea to Plate Tectonics

Burial, compaction, and porosities in a subduction zone

Online Investigation of an Island Arc Volcano: Anatahan, Mariana Arc

A tour of the Mariana Subduction System

Chemical Inputs and Outputs at Subduction Zones

Pick the lesson that suits your class by visiting the complete list of MARGINS mini-lessons here:

http://serc.carleton.edu/margins

To submit your own mini-lesson, see the box below. For more mini-lessons information, contact Jeff Ryan (ryan@shell.cas.usf.edu), Don Reed (dreed@geosun.sjsu.edu), Cathy Manduca (cmanduca@carleton.edu) or the MARGINS Office (margins@nsf-margins.org).

Submit a MARGINS Mini-Lessonhttp://serc.carleton.edu/margins/minilessons.html

Submission of a mini-lesson is now open to any interested educator and/or researcher who would like to contribute an example from

his/her own teaching using MARGINS data or research for web-based classes.• MARGINS has been awarded a NSF Curriculum, and Laboratory Improvement (CCLI) Phase I grant to develop web-based

undergraduate classroom teaching modules, in cooperation with the Science Education Resource Center of Carleton Col-lege.

• MARGINS Mini-Lessons are modular learning materials that repurpose the data resources, visualizations, and other infor-mation sources developed through MARGINS and MARGINS-related research for use in examining fundamental earth processes in undergraduate classrooms from a multidisciplinary perspective.

• MARGINS Mini-Lessons are based on best practices in geoscience pedagogy and in the construction of digital educational products. As a means of making this collection very broadly applicable, Virtual Expeditions and Web-deliverable Labora-tory/Classroom Exercises are being developed (http://serc.carleton.edu/margins/collection.html).

We welcome contributions from any interested educator and/or researcher involved in earth sciences. To submit a Mini-Lesson go to: http://serc.carleton.edu/margins/submit-minilesson.html. Contact: Cathy Manduca (cmanduca@carleton.edu), Jeff Ryan (ryan@shell.cas.usf.edu), Don Reed (dreed@geosun.sjsu.edu) or the MARGINS Office (margins@nsf-margins.org)

MARGINS Newsletter No. 20, Spring 2008 Page 31

Demian SafferDepartment of Geosciences

Pennsylvania State University 310 Deike Building

University Park, PA 16802Tel: (814) 865-7965

e-mail: dsaffer@geosc.psu.edu

John SwensonDepartment of Geological Sciences

University of Minnesota Duluth1110 Kirby Drive

Duluth, MN 55812Tel: (218) 726-6844

e-mail: jswenso2@d.umn.edu

Paul J. Umhoefer*Department of Geology, Box 4099

Northern Arizona UniversityFlagstaff, AZ 86011Tel: (928) 523-6464

e-mail: paul.umhoefer@nau.edu

MARGINS Steering Committee

Bilal HaqMarine Geology and Geophysics Program

Division of Ocean SciencesTel: (703) 292-8582Fax: (703) 292-9085

e-mail: bhaq@nsf.gov

Deborah SmithOcean Drilling Program

Division of Ocean SciencesTel: (703) 292-7484Fax: (703) 292-9085

e-mail: dksmith@nsf.gov

William LeemanPetrology and Geochemistry Program

Division of Earth SciencesTel: (703) 292-7411Fax: (703) 292-9025

e-mail: wleeman@nsf.gov

NSF Program DirectorsNational Science Foundation, 4201 Wilson Boulevard, Arlington, Virginia 22230

Contact Information

Geoffrey Abers*, ChairLamont-Doherty Earth Observatory

of Columbia UniversityP.O. Box 1000

Palisades, NY 10964Tel: (845) 365-8539

e-mail: abers@ldeo.columbia.edu

Nathan BangsInstitute for Geophysics, The University of Texas

J.J. Pickle Research Campus, Bldg. 19610100 Burnet Road (R2200)

Austin, TX 78758-4445Tel: (512) 471-0424

e-mail: nathan@utig.ig.utexas.edu

Mark BehnWoods Hole Oceanographic Institution

Mailstop 22Clark 260B

Woods Hole, MA 02543Tel: (508) 289-3637

e-mail: mbehn@whoi.edu

Susan BilekDept of Earth & Environmental Science

MSEC 354 New Mexico Tech

Socorro, NM 87801 Tel: (575) 835-6510

e-mail: sbilek@nmt.edu

Thomas DunneBren School of Environmental Science & Manage-

ment University of California, Santa BarbaraBren Hall 3510

Santa Barbara, California 93106-5131Tel: (805) 893-7557

e-mail: tdunne@bren.ucsb.edu

Cynthia EbingerDepartment of Earth and Environmental Sciences

University of Rochester227 Hutchinson HallRochester, NY 14627Tel: (585) 276-3364

e-mail: ebinger@earth.rochester.edu

MARGINS OfficeLamont-Doherty Earth Observatory, P.O. Box 1000, 61 Route 9W, Palisades, NY 10964

Tel: (845) 365-8711, Fax: (845) 365-8150, E-mail: margins@nsf-margins.org, Website: www.nsf-margins.org

Chair: Geoff Abers (abers@bu.edu), Coordinator: Niva Ranjeet (ranjeet@ldeo.columbia.edu), Senior Science Coordinator: Andrew Goodwillie (andrewg@ldeo.columbia.edu) & Administrator: Kathryn Kennedy (kathryn@ldeo.columbia.edu)

James GillEarth Sciences Department

University of California, Santa Cruz137 Applied Sciences

1156 High StreetSanta Cruz, CA 95064

Tel: 831-459-2425e-mail: jgill@es.ucsc.edu

W. Steven HolbrookDepartment of Geology and Geophysics

University of WyomingEarth Sciences Building 3016

Laramie, WY 82071-3006Tel: (307) 766-2724

e-mail: steveh@uwyo.edu

Peter van KekenDepartment of Geological Sciences

425 East University AvenueUniversity of Michigan

Ann Arbor, MI 48109-1063Tel: (734) 764-1497

e-mail: keken@umich.edu

Steve KuehlVirginia Institute of Marine Science

College of William and MaryHolben House Room 201

Gloucester Point, VA 23062Tel: (804) 684-7118

e-mail: kuehl@vims.edu

Don Reed*Department of Geology

San Jose State UniversitySan Jose, CA 95192-0102

Tel: (408) 924-5036e-mail: dreed@geosun.sjsu.edu

Jeff Ryan*Department of Geology

University of South Florida 4202 East Fowler Ave., SCA 528

Tampa, FL 33620-5201 Tel: (813) 974-1598/6287

e-mail: ryan@chuma.cas.usf.edu

Cathy Manduca, Carleton College,e-mail: cmanduca@carleton.edu

Rosemary Hickey-Vargas, Florida Interna-tional University, e-mail: hickey@fiu.edu

Ex-Officio:Andrew Goodwillie,

Lamonth-Doherty Earth Observatory, e-mail: andrewg@ldeo.columbia.edu

Education Advisory Committee Members above marked * plus:

This information is also posted on the MARGINS website, where it is

continuously updated.

This newsletter is supported by the National Science Foundation under Grant No. OCE 08-23714. Any opinions, findings, and conclusions expressed in it are those of the authors and do not necessarily reflect the views of the National Science Foundation.

Upcoming MARGINS Meeting:The Next Decade of the Seismogenic Zone Experiment

Mount Hood, Oregon, September 22-26, 2008Applications Due June 1, 2008

Conveners: N. Bangs (nathan@utig.ig.utexas.edu), D. Reed (Dreed@geosun.sjsu.edu), D. Saffer (Dsaffer@geosc.psu.edu), S. Schwartz (susan@pmc.ucsc.edu)

www.nsf-margins.org/SEIZE/2008

This newsletter is produced on behalf of MARGINS by the MARGINS Office.Edited and Designed by the MARGINS Office.

NSF-MARGINS Proposal and Post-doctoral Fellowship Deadline:

July 1, 2008.

Published semi-annually by theMARGINS Office

Lamont-Doherty Earth Observatoryof Columbia University

61 Route 9WPalisades, NY 10964 USA

New

slet

ter #

20,

Spr

ing

2008