RECENT ADVANCES IN SEISMIC AND INFRASONIC … · ANALYSES OF VOLCANIC ERUPTIONS AND POTENTIAL FOR USING ... Highlight recent advances in seismic and infrasonic analyses of volcanic

R E C E N T A D VA N C E S I N S E I S M I C A N D I N F R A S O N I C A N A LY S E S O F V O L C A N I C E R U P T I O N S A N D P O T E N T I A L F O R U S I N G E A RT H S C O P E D ATA

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D AV I D F E E W I L S O N A L A S K A T E C H N I C A L C E N T E R , A L A S K A V O L C A N O O B S E RVAT O RY G E O P H Y S I C A L I N S T I T U T E , U N I V E R S I T Y O F A L A S K A FA I R B A N K S

R O B I N M AT O Z A D E PA RT M E N T O F E A RT H S C I E N C E A N D E A RT H R E S E A R C H I N S T I T U T E U C S A N TA B A R B A R A

M AT T H A N E Y U . S . G E O L O G I C A L S U RV E Y, A L A S K A V O L C A N O O B S E RVAT O RY

M O T I VAT I O N A N D A I M• Arrival of Earthscope in Alaska provides opportunity to study and improve

monitoring of volcanic eruptions

• This talk:

1. Highlight recent advances in seismic and infrasonic analyses of volcanic eruptions

2. Discuss potential of using Earthscope data for monitoring and studying volcanic eruptions

2Okmok Volcano, 2008 (AVO)

P O T E N T I A L V O L C A N I C H A Z A R D R E L AT E D U S E S O F E A RT H S C O P E S E I S M I C A N D I N F R A S O U N D D ATA

Volcanoes in AK • >90 volcanoes active in

Holocene, >50 have erupted in past 200 years

• >2 eruptions per year

• Most volcanoes are remote, so primary hazard is aviation

• Monitored by Alaska Volcano Observatory (AVO) using combination of seismic, infrasonic, geodetic networks, as well remote sensing, geological and geochemical studies

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Recent Eruptions • Pavlof: 2013 and 2014

• Veniaminof: 2013

• Cleveland: 2013 and 2014

• Shishaldin: 2014-15


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A L A S K A : AV O A N D A E C N E T W O R K S

Existing seismic networks

• AVO: ~220 seismic stations

• Primarily on AK Peninsula and Aleutian Islands

• Alaska Earthquake Center (AEC): ~125 seismic stations

• Primarily in southern and interior AK

• 13 infrasound sites by UAF-GI and AVO

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A L A S K A : 2 0 1 4

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Transportable Array

• 25 stations added or upgrade

• Majority in interior AK, Kenai Peninsula

A L A S K A : 2 0 1 5

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Transportable Array

• 82 stations to be added or upgraded

• New stations to be added near active, hazardous Cook Inlet volcanoes

A L A S K A : 2 0 1 6

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Transportable Array


• Many in northern AK and Canada

• New or upgraded stations in AK Peninsula and Aleutians

A L A S K A : 2 0 1 7

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Transportable Array


• New or upgraded stations in western AK and northern Yukon

R E C E N T A D VA N C E S : L A R G E - N S E I S M I C

iMUSH • Univ Washington, Rice, Columbia Univ, Oregon State,

ETH-Zurich, USGS • Goal: image and interpret the crust and upper mantle

with Large-N network • MT, active and passive source seismic integrated with

geochemical and petrological data • Funded via Earthscope and GeoPRISMS, with USGS

and Forest Service assistance

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imush.org

VolcanoSRI • Georgia State, Michigan State, UNC • Goal: large-scale sensor network of low-cost

stations that computes real-time, full-scale, 3-D fluid dynamics of the volcano conduit system

• 4D Volcano Tomography in a Large-Scale Sensor Network

• Funded via NSF CDI

http://sensorweb.cs.gsu.edu

http://sensorweb.cs.gsu.edu

C U R R E N T V O L C A N O S E I S M I C P R O J E C T S I N A L A S K A

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Unalaska and Akutan • UC Riverside, University of Wisconsin-Madison • Goal: Tectonic and volcanic seismicity, as well as image subsurface • 4 hybrid mini seismic arrays and 6 stand-alone seismic stations on

Unalaska and Akutan Islands • Funded via Earthscope, collaboration with AVO

Image courtesy AVO

Unimak-Cleveland • Carnegie Institution of Washington, Columbia University • Goal: Analyze volatile content of magmas at a number of depths • Combined Geochemical and Geophysical study • Geophysics focused on the active Cleveland Volcano • Funded via GeoPRISMS, collaboration with AVO

Okmok • UCSD, University of Wisconsin-Madison • Goal: Seismic and electromagnetic imaging of magma plumbing from slab to surface • 13 campaign broadband stations, deployed for 1 year • 62 land-based MT sites, 300 km line of marine MT stations in a 2D arc-normal line

from the trench into the Bering Sea • Funded via GeoPRISMS, collaboration with AVO/USGS

Figure courtesy Matt Haney

NASA Earth Observatory image by Jeff Williams

S E I S M I C T O M O G R A P H Y

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• Syracuse et al. [2015]: joint inversion using local body waves and surface wave dispersion curves from ambient noise at Makushin and Akutan Volcanoes

• Complex structure with low Vp anomaly at 7 km depth and high Vp anomaly leading to surface

O K M O K V O L C A N I C T R E M O R

• Tremor back-projection: Spectral whitening, time shift, and compute stack power for candidate source locations

• At Okmok, virtually no path effects in the 0.2-0.3 Hz band [Haney, 2010]

• Time shifting based on a homogeneous surface wave velocity model of 2.7 km/s [Masterlark et al., 2010]

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O K M O K V O L C A N I C T R E M O R

• First demonstration of back-projection for tracking changing volcanic tremor

• Waveform inversion yielded a shallow depth for tremor close to back-projection location

• Array deconvolution needed to resolve km-scale changes in tremor location

• Tremor imaging revealed 2 August escalation due to a shift toward intracaldera lake

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1-2 hours prior to tremor escalation

0-1 hours prior to tremor escalation

Typical tremor

location

Tremor movement toward caldera wall

[Haney, 2014]

Apparent Tremor Movement

Cone D Lake

Caldera Wall

NORTH

R E C E N T A D VA N C E S : A C O U S T I C

• Workshop held by IAVCEI Volcano Acoustics Commission at Sakurajima Volcano, Japan

• Infrasound data uploaded to IRIS-DMC as benchmark dataset for the acoustic community to use in education, training, and research.

• Focus Section in Seismological Research Letters

18Infrasound data sped up 40x

Sakurajima Volcano, Japan

S A K U R A J I M A V O L C A N O : D E P L O Y M E N T A N D T O P O G R A P H Y

• Sensors deployed at various angles and distances to vent

• Topographic obstructions between vent and multiple sensors

• Significant waveform variability —> Propagation must be considered before the source can be evaluated-even locally! [e.g. Matoza et al., 2009; Lacanna and Ripepe, 2012];

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a) b)

0 1000 2000 3000 4000 5000 60000

500

1000

Elev

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n [m

]

ARI

0 1000 2000 3000 4000 5000 60000

500

1000

Elev

atio

n [m

]

HAR

0 1000 2000 3000 4000 5000 60000

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1000

Elev

atio

n [m

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KOM

0 1000 2000 3000 4000 5000 60000

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1000

Elev

atio

n [m

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KUR

0 1000 2000 3000 4000 5000 60000

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Elev

atio

n [m

]

SVO

Distance [m]

−1000−500

0500

1000 ARI2311 m, 186o

Pres

sure

[Pa]

−1000−500

0500

1000 HAR3390 m, 299o

−1000−500

0500

1000 KOM4481 m, 26o

−1000−500

0500

1000 KUR3420 m, 81o

11:02:00 11:02:05 11:02:10 11:02:15 11:02:20

−1000−500

0500

1000 SVO6221 m, 281o

21 Jul UTC Time

[Fee et al., 2014]

S A K U R A J I M A M O D E L I N G• Finite-Difference Time-Domain Modeling

• 3-D GPU-accelerated, high-resolution DEM

• Anisotropic radiation due to topography

• Simple source for synthetics suggests waveform complexity from topography

20[Kim et al., in press][Kim and Lees, 2014]

S A K U R A J I M A WAV E F O R M I N V E R S I O N

• Excellent waveform fit to observations

• Monopole source time history (volume flux)

• 3-D Green's function: smoothly decreasing

• Half-space Green's function: oscillatory curve

• First acoustic inversion with computed, 3-D Green’s functions

• Volume/mass flux critical parameter for hazard mitigation

21[Kim et al., in press]

L O C A L A N D R E M O T E I N F R A S O U N D C O M PA R I S O N

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• Unique opportunity to compare local (12 km) and remote (547 km) data and examine long-range propagation

• High waveform similarity between local (red) and remote (black) stations

• Principal infrasound waveform features apparent at 547 km (IS53) for most events

[Fee et al., 2013]

P R O PA G AT I O N M O D E L I N G A N D C R O S S - C O R R E L AT I O N

• Propagation:

• Deep atmospheric waveguide between ~40-60 km likely responsible for high waveform similarity

• Ray tracing predicts a single ground reflection between source and receiver

[Fee et al., 2013]

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[Fee et al., 2013]

Winds Sound Speed Sound Propagation

• Compute cross-correlation between local and remote data

• Hilbert transform predicted from ray theory (90° phase shift) improves cross-correlation to 0.89

• Remote infrasound can provide good representation of local infrasound

G L O B A L C ATA L O G I N G O F E X P L O S I V E V O L C A N I S M• Project led by Robin Matoza (UCSB)

• Global association and location: brute force grid-search cross-bearings approach

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e.g., +/-

longitud

latitud

G L O B A L C ATA L O G I N G O F E X P L O S I V E V O L C A N I S M• Association and location: brute force grid-search cross-bearings approach

• Example: Sarychev Peak, 2009

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[Matoza et al., 2011]

S E I S M O A C O U S T I C S T U D I E S : C L E V E L A N D V O L C A N O , A K

• One of the most active and remote volcanoes in the Aleutian arc

• Mostly small, ash-producing eruptions (<25,000’), but occasionally >33,000’

• No real-time, local, seismic network due to logistical challenges (closest seismic station is 75 km)

• Primarily monitored using remote sensing

OKAKS

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• Ground-coupled airwaves apparent on seismic network

• Not coherent across network, thus cross-correlation techniques fail

C L E V E L A N D V O L C A N O - D E T E C T A N D N O T I F Y

From: David Fee [email protected]: Cleveland Volcano Dillingham Infrasound Detection Alert: 13-Apr-2012 1600 - 13-Apr-2012 1700 UTCDate: April 13, 2012 10:08:14 AM PDTTo: David Fee <[email protected]>, [email protected], Silvio De Angelis <[email protected]>, [email protected], [email protected], [email protected], Colin Rowell <[email protected]> Cleveland Infrasound Detection AlertDillingham Infrasound Array, 992 km from source

Dillingham Detection Time: 13-Apr-2012 16:54:27 UTCApprox. Origin Time: 13-Apr-2012 16:02:47 UTCMax Pressure Amplitude: 0.143 PaMax Fisher Ratio: 237•

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Dillingham - 992 km

Infrasound

Wave Velocity

Back-Azimuth

Automated detections send alerts to AVO personnel

Dec 2011 – Aug 2012 Detections: ~7/20 in satellite imagery 19/20 events with infrasound

[De Angelis et al., 2012]

C O - L O C AT E D S E I S M I C A N D A C O U S T I C S E N S O R S

Filtered Waveforms

Acoustic spectrogram

Seismic spectrogram

5-10 Hz cross-correlation

Coherence spectrogram

Phase spectrogram

Infrasound array processing

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~5 m

acoustic

seismic

[Matoza and Fee, 2014]

• Seismic-acoustic cross-correlation [Ichihara et al., 2012] and coherence [Matoza and Fee, 2014]

Utilize co-located seismic and acoustic sensors to detect:

1) acoustic signals without an array

2) ground-coupled energy on seismometers

8 March 2005, Mount St. Helens

E X A M P L E U S E O F TA : C H E LYA B I N S K M E T E O R

• TOLK (USArray TA station) in Northern Alaska

• Distance ~6000 km

• Acoustic-seismic coherence analysis

• Narrowband 2-4 Hz coherence/coupling

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acousticseismic

E X A M P L E U S E O F TA : G R O U N D - C O U P L E D A I R WAV E D E T E C T I O N A N D L O C AT I O N

• Pavlof: acoustic waves from explosions commonly recorded on seismometers

• Time Difference of Arrival: Station-Pair Double Difference and srcLoc

• Hundreds of events located on SE flank, consistent with vent location

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7-20 Hz waveforms, C=0.13 Envelope (smoothed), C=0.49 (0.76)

E X A M P L E U S E O F TA : R E V E R S E T I M E M I G R AT I O N

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• Acoustic waves recorded on seismic and infrasound sensors of sparse network

• Waveforms not coherent between stations-use amplitude envelope

• Reverse time migration (back-projection) of sparse network data – both seismic and acoustic

• Provides relatively high resolution location

• Applicable to volcanic eruptions

[Walker et al., 2010]

[Walker et al., 2010]

E X A M P L E U S E O F TA : R E G I O N A L E R U P T I O N T R E M O R

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• Remote, catastrophic eruption of Kasatochi Volcano, Alaska in 2008

• Prejean and Brodsky [2009] related far-field surface waves to mass eruption rate/plume height

C O N C L U S I O N S A N D F U T U R E W O R K

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• Opportunity to use existing networks and Earthscope data to monitor and study volcanic eruptions in Alaska - Detect, locate, image, characterize, and quantify volcanic source - Discriminate between different events *Relatively sparse network not always near volcanoes *Focused deployments for imaging, tracking tremor, etc

• Utilize co-located seismic and acoustic sensors to detect: - Acoustic signals without an array - Ground-coupled energy on seismometers

• Stations near volcanoes will improve eq detection and location • Integrate with PBO and geologic data

Documents

RECENT ADVANCES IN SEISMIC AND INFRASONIC … · ANALYSES OF VOLCANIC ERUPTIONS AND POTENTIAL FOR USING ... Highlight recent advances in seismic and infrasonic analyses of volcanic