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NASA Tests GPS Monitoring System for Big U.S. Earthquakes

Figure 1: Diagram showing how earthquakes can ...
Figure 1: Diagram showing how earthquakes can generate a tsunami. (Photo credit: Wikipedia)
April 24, 2012

Steve Cole 
Headquarters, Washington                                    

Alan Buis 
Jet Propulsion Laboratory, Pasadena, Calif. 

RELEASE: 12-108


WASHINGTON -- The space-based technology that lets GPS-equipped 
motorists constantly update their precise location will undergo a 
major test of its ability to rapidly pinpoint the location and 
magnitude of strong earthquakes across the western United States. 
Results from the new Real-time Earthquake Analysis for Disaster 
(READI) Mitigation Network soon could be used to assist prompt 
disaster response and more accurate tsunami warnings. 

The new research network builds on decades of technology development 
supported by the National Science Foundation, the Department of 
Defense, NASA, and the U.S. Geological Survey (USGS). The network 
uses real-time GPS measurements from nearly 500 stations throughout 
California, Oregon and Washington. When a large earthquake is 
detected, GPS data are used to automatically calculate its vital 
characteristics including location, magnitude and details about the 
fault rupture. 

"With the READI network we are enabling continued development of 
real-time GPS technologies to advance national and international 
early warning disaster systems," said Craig Dobson, natural hazards 
program manager in the Earth Science Division at NASA Headquarters in 
Washington. "This prototype system is a significant step towards 
realizing the goal of providing Pacific basin-wide natural hazards 
capability around the Pacific 'Ring of Fire.'" 

Accurate and rapid identification of earthquakes of magnitude 6.0 and 
stronger is critical for disaster response and mitigation efforts, 
especially for tsunamis. Calculating the strength of a tsunami 
requires detailed knowledge of the size of the earthquake and 
associated ground movements. Acquiring this type of data for very 
large earthquakes is a challenge for traditional seismological 
instruments that measure ground shaking. 

High-precision, second-by-second measurements of ground displacements 
using GPS have been shown to reduce the time needed to characterize 
large earthquakes and to increase the accuracy of subsequent tsunami 
predictions. After the capabilities of the network have been fully 
demonstrated, it is intended to be used by appropriate natural hazard 
monitoring agencies. USGS and the National Oceanic and Atmospheric 
Administration are responsible for detecting and issuing warnings on 
earthquakes and tsunamis, respectively. 

"By using GPS to measure ground deformation from large earthquakes, we 
can reduce the time needed to locate and characterize the damage from 
large seismic events to several minutes," said Yehuda Bock, director 
of Scripps Institution of Oceanography's Orbit and Permanent Array 
Center in La Jolla, Calif. "We now are poised to fully test the 
prototype system this year." 

The READI network is a collaboration of many institutions including 
Scripps at the University of California in San Diego; Central 
Washington University in Ellensburg; the University of Nevada in 
Reno; California Institute of Technology/Jet Propulsion Laboratory 
(JPL) in Pasadena; UNAVCO in Boulder, Colo.; and the University of 
California at Berkeley. 

NASA, NSF, USGS, and other federal, state, and local partners support 
the GPS stations in the network, including the EarthScope Plate 
Boundary Observatory, the Pacific Northwest Geodetic Array, the Bay 
Area Regional Deformation Array and the California Real-Time Network. 

"The relatively small investments in GPS-based natural hazards systems 
have revolutionized the way we view the Earth and allowed us to 
develop this prototype system with great potential benefits for the 
infrastructure and population in earthquake-prone states in the 
western United States," said Frank Webb, Earth Science Advanced 
Mission Concepts program manager at JPL. 

The READI network is the outgrowth of nearly 25 years of U.S. 
government research efforts to develop the capabilities and 
applications of GPS technology. The GPS satellite system was created 
by the Department of Defense for military and ultimately civil 
positioning needs. NASA leveraged this investment by supporting 
development of a global GPS signal receiving network to improve the 
accuracy and utility of GPS positioning information. Today that 
capability provides real-time, pinpoint positioning and timing for a 
wide variety of uses from agriculture to Earth exploration. 

"Conventional seismic networks have consistently struggled to rapidly 
identify the true size of great earthquakes during the last decade," 
said Timothy Melbourne, director of the Central Washington 
University's Pacific Northwest Geodetic Array. "This GPS system is 
more likely to provide accurate and rapid estimates of the location 
and amount of fault slip to fire, utility, medical and other 
first-response teams." 
The GPS earthquake detection capability was first demonstrated by 
NASA-supported research on a major 2004 Sumatra quake conducted by 
Geoffrey Blewitt and colleagues at the University of Nevada in Reno. 

For more information about NASA programs, visit: