1 GPS Requirements for Tsunami Detection Y. Tony Song & Geoff Blewitt Collaborators: Yoaz Bar- Yoaz Bar- Sever, Richard Gross, Sever, Richard Gross, Vindell Hsu, Kenneth Vindell Hsu, Kenneth Hudnut, Hans-Peter Plag , Hudnut, Hans-Peter Plag , Mark Simons, and Frank Webb Mark Simons, and Frank Webb Jet Propulsion Laboratory Jet Propulsion Laboratory NOAA (PTWC) NOAA (PTWC) USGS USGS Caltech Caltech University of Nevada Reno University of Nevada Reno
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1 GPS Requirements for Tsunami Detection Y. Tony Song & Geoff Blewitt Yoaz Bar-Sever, Richard Gross, Vindell Hsu, Kenneth Hudnut, Hans-Peter Plag, Mark.
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GPS Requirements for Tsunami Detection
Y. Tony Song & Geoff Blewitt
Collaborators:Yoaz Bar-Sever, Yoaz Bar-Sever, Richard Gross, Vindell Hsu, Kenneth Richard Gross, Vindell Hsu, Kenneth Hudnut, Hans-Peter Plag ,Hudnut, Hans-Peter Plag ,Mark Simons, and Frank WebbMark Simons, and Frank Webb
Jet Propulsion Laboratory Jet Propulsion Laboratory NOAA (PTWC)NOAA (PTWC)USGS USGS Caltech Caltech University of Nevada RenoUniversity of Nevada Reno
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Tsunami Basics
• Tsunamis are usually caused by undersea earthquakes.
• Tsunami waves travel at a speed of ~800 km/hour (or 200 m/s) in deep oceans.
• A meter-height tsunami in the deep ocean can grow to tens of meters at coast.
• Unlike wind-driven
ocean waves that are only a disturbance of the sea surface, the tsunami wave energy extends to the ocean bottom.
2004 Indian Ocean Tsunami
Tsunamis occur after earthquakes
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Conclusion: Earthquake magnitude does not determine tsunami impact.
Date Location Magnitude Early Warning? Fatalities
26 Dec 2004 Sumatra 9.2 No Tsunami death~230,000
28 Mar 2005
19 July 2005
Nias Island
North California
8.7
7.7
Panic evacuation
False alarm
Evacuation killed ~100
No tsunami
27 Jan 2006
3 May 2006
19 July 2006
15 Nov 2006
Benda Sea
Tonga
South Java
Kuril Islands
7.6
8.0
7.7
8.3
?
False Alarm
No
False alarm/alert
No tsunami
No tsunami
Tsunami death~730
Small tsunami
13 Jan 2007
1 Apr 2007
15 Aug 2007
12 Sep 2007
Kuril Islands
Solomon Island
Central Peru
South Sumatra
8.1
8.0
8.0
8.4
False alarm/alert
No
Alert
Alert
No tsunami
Tsunami death~54
No tsunami
No tsunami
Recent Tsunami Events
11 events in 4 years
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The Consequence of Late Warnings
2004: tsunami death ~230,000
2006: tsunami death ~730
2007: tsunami death ~54
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The Consequence of False Alarms
State of Hawaii’s estimation: an evacuation from a tsunami alarm would have cost the state $58.2 million in economic losses (Eddie Bernard, 1996).
Since 1982, tsunami warnings based on earthquake magnitude have produced false alarms 16 out of 16 in Pacific (U.S. Government Accountability Office, GAO-06-519).
Panic evacuation killed ~100 in March 2005
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Earthquakes Occur Near Coast
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GPS ApproachGPS ApproachSong, Y. T., Detecting tsunami genesis and Song, Y. T., Detecting tsunami genesis and
scales directly from coastal GPS scales directly from coastal GPS stations, stations, GRLGRL, , 3434, , doi:10.1029/2007GL03168 (2007).doi:10.1029/2007GL03168 (2007).
Tsunami TheoryTsunami TheorySong et al., Horizontal impulses of faulting continental Song et al., Horizontal impulses of faulting continental