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The Importance of International Seismic Networks for Tsunami Warning. Stuart A. Weinstein and Charles McCreery, Richard Hagemeyer Pacific Tsunami Warning Center. Int. Seismic Networks Are Instrumental To The Tsunami Warning System - PowerPoint PPT Presentation
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23 August 2005 GEOSS Workshop
The Importance of International Seismic Networks for Tsunami Warning
Stuart A. Weinstein and Charles McCreery,
Richard Hagemeyer Pacific Tsunami Warning Center
Int. Seismic Networks Are Int. Seismic Networks Are Instrumental To The Tsunami Instrumental To The Tsunami
Warning SystemWarning System
• They allow the warning system to They allow the warning system to respond quickly to any potential respond quickly to any potential tsunamigenic earthquake occurring tsunamigenic earthquake occurring anywhere in the world.anywhere in the world.
• Contribute to the monitoring of “local” Contribute to the monitoring of “local” earthquakes.earthquakes.
Int. Seismic Networks Are Int. Seismic Networks Are Instrumental To The Tsunami Instrumental To The Tsunami
Warning SystemWarning System
• With a Satellite dish, PTWC has a first With a Satellite dish, PTWC has a first hop capability for several instruments.hop capability for several instruments.
• Currently PTWC, receives MIDW, RPN, Currently PTWC, receives MIDW, RPN, JOHN and WAKE, with XMAS, KANT, JOHN and WAKE, with XMAS, KANT, and TARA to be received in the near and TARA to be received in the near future.future.
Earthquake MonitoringEarthquake Monitoring
• Near Real Time Seismic Data From Near Real Time Seismic Data From Over 130 Broadband Stations.Over 130 Broadband Stations.
• Digital AlarmsDigital Alarms
• Automatic P-Wave Picking And Automatic P-Wave Picking And Association (GLASS, LOC_ATWC)Association (GLASS, LOC_ATWC)
• Magnitude Estimation: Mwp, Mm, MsMagnitude Estimation: Mwp, Mm, Ms
• Energy/Moment ratio Energy/Moment ratio ewman and ewman and Okal)Okal)
Broadband Seismometer Distribution
Vertical Component Only
Earthquake MonitoringEarthquake Monitoring
Mwp (Tsuboi et al.)Mwp (Tsuboi et al.)
• P-wave method (fast!) developed for deep P-wave method (fast!) developed for deep focus earthquakes found to work for shallow focus earthquakes found to work for shallow quakes.quakes.
• Less affected by Saturation Problem Less affected by Saturation Problem Associated with MAssociated with Ms.
• Can be fooled by complex rupture (Peru Can be fooled by complex rupture (Peru 2001).2001).
Mwp and Local Earthquakes
Mwp is limited by the trade off between the S-P travel time, and the source duration of the event.
Appears to work well at less than 5 degrees epicentral distance. Depending on the Mw and source length, Mwp provides an estimate that is low by an amount that decreases between 1-5 degrees epicentral distance.
Will automate it for local earthquakes.
84 Mwp Observations Within 5 Degrees of The Epicenter
Earthquake MonitoringEarthquake Monitoring
Mantle Magnitude (Okal and Talandier)Mantle Magnitude (Okal and Talandier)
• Long Period Rayleigh Waves that Sample the Long Period Rayleigh Waves that Sample the Upper Mantle (Mantle Waves).Upper Mantle (Mantle Waves).
• Overcomes Saturation Problem Associated Overcomes Saturation Problem Associated with Mwith Ms (Variable Period Magnitude).
• Less Effected By Rupture Slowness Or Less Effected By Rupture Slowness Or Complexity.Complexity.
• Quicker Than Computing CMT.Quicker Than Computing CMT.
Sampling by Max Mm
Sampling by Max of Mean Mm(T)
Harvard Mw
Mea
n R
esid
ual
Mea
n R
esid
ual
Mea
n R
esid
ual
Mea
n R
esid
ual
273s163s
51s
EARTHWORM ARCHITECTURE
ASSOCHYPS
MODULE
MAGNMODULE
IMPORTMODULE
PICKMODULE
EXPORTMODULE
SINGLE PLATFORM (NT OR SOLARIS)
LAN/WAN
LAN/WAN
WAVE-FORMRING
PICKRING
HYPSRING
• FREE AND AVAILABLE OFF OF THE WEBFREE AND AVAILABLE OFF OF THE WEB
HTTP://GLDBRICK.CR.USGS.GOVHTTP://GLDBRICK.CR.USGS.GOV
• OPEN SOURCE (FREE SOURCE CODE)OPEN SOURCE (FREE SOURCE CODE)
• LARGE AND GROWING USER COMMUNITYLARGE AND GROWING USER COMMUNITY
• USERS GROUPS FOR PROBLEMSUSERS GROUPS FOR PROBLEMS
• USERS GROUP FOR DEVELOPERSUSERS GROUP FOR DEVELOPERS
• ANSS STANDARD FOR US SEISMIC NETWORKSANSS STANDARD FOR US SEISMIC NETWORKS
IMPORTANT EARTHWORM FEATURES
ISSUE TIME OF PTWC INITIAL BULLETINS FOR TELESEISMS
0
10
20
30
40
50
60
70
80
90
100
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
EVENT TIME (YEAR)
MIN
UT
ES
SIN
CE
QU
AK
E
ISSUE TIME OF PTWC BULLETINS FOR HAWAII EVENTS
0
5
10
15
20
25
30
1994 1996 1998 2000 2002 2004 2006
EVENT TIME (YEAR)
EL
AP
SE
D M
INU
TE
S
Food for ThoughtFood for Thought
• Greater global network density. How dense?Greater global network density. How dense?
• Leverage off of the assets being devoted to Leverage off of the assets being devoted to DART systemsDART systems:
• Communications.Communications.
• Successor to the STS-1 very broadband Successor to the STS-1 very broadband seismometer.seismometer.
•Ocean Bottom Seismometers•Hydrophone Arrays