Toward Real-Time GPS for Tsunami Warning Systems and Post-Earthquake Damage Assessment and Emergency Response
Geoffrey Blewitt(1), Corne Kreemer(1), William Hammond(1), Hans-Peter Plag(1), Seth Stein(2), Emile Okal(2), Yoaz Bar-Sever(3), Richard Gross(3), Vindell Hsu(4), Kenneth Hudnut(5), Mark Simons(6), Tony Song(3) and Frank Webb(3)
(1) University of Nevada, Reno, 1664 N. Virginia St., Reno, NV 89557-0178, United States
(2) Northwestern University, Department of Geological Sciences, Evanston, Illinois, United States
(3) Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
(4) NOAA / NWS, 91-270 Fort Weaver Road, Hawaii 96706-2928, United States
(5) United States Geological Survey, 525 South Wilson Avenue, Pasadena, CA 91106-3212, United States
(6) California Institute of Technology, 252-21 Caltech, Pasadena, CA 91125, United States
Abstract

The 26 December 2004 Sumatra earthquake(Mw 9.2\u20139.3) generated the most deadly tsunami in history. Yet within the first hour, the true danger of a major oceanwide tsunami was not indicated by seismic magnitude estimates, which were far too low (Mw 8.0\u20138.5). This problem relates to the inherent saturation of early seismic wave methods. Here we show that the earthquake\u2019s true size and tsunami potential can be determined using Global Positioning System (GPS) data up to only 15 min after earthquake initiation, by tracking the mean displacement of the Earth\u2019s surface associated with the arrival of seismic waves. Within minutes, displacements of >10 mm are detectable as far away as India, consistent with results using weeks of data after the event. These displacements imply Mw 9.0 ± 0.1, indicating a high tsunami potential. This suggests existing GPS infrastructure could be developed into an effective component of tsunami warning systems. We present our recent findings on the design specifications a real-time GPS component of future tsunami warning systems.

In the USA it is now being proposed jointly by NASA, NOAA and USGS to exploit the increasingly available global and regional real-time GPS data from NASA\u2019s operational Global Differential GPS (GDGPS) System to enable more accurate and timely assessment of the magnitude and mechanism of large earthquakes, as well as the magnitude and direction of resulting tsunamis. The idea is to use GPS-based information in addition to existing data types to enhance the USGS operational system for post-earthquake damage assessment and emergency response, and, improve tsunami warnings by NOAA\u2019s Pacific Tsunami Warning Center (PTWC).