American Geophysical Union, Fall 2008
A promising early-warning system for geological and atmospheric hazards - earthquakes, floods, landslides and tsunamis - is currently being tested in Southern California. The California Real Time Network (CRTN) developed by the Scripps Orbit and Permanent Array Center (SOPAC) at Scripps Institution of Oceanography at UC San Diego offers real-time information of an event that sets into motion a warning system before the event reaches highly populated regions. Researchers hope the system will help protect lives and support disaster preparedness and hazard mitigation.
Seven-story structure at UCSD's Englekirk Structural Engineering Center is used to simulate earthquake effects on buildings.
The network operated by Yehuda Bock, director of SOPAC and the Scripps California Spatial Reference Center, is a research test bed for early warning systems of natural hazards, geodetic referencing and weather forecasting. CRTN, which consists of 75 GPS stations throughout Southern California, monitors ground movements from satellites above the earth and sends data streaming back every second to the Scripps campus in La Jolla, Calif. During the first sign of a magnitude-6 and higher event, the system automatically triggers an email alert to subscribers.
During an invited talk at the 2008 American Geophysical Union Fall Meeting, titled "Fusion of High-Rate GPS and Seismic Data: Application to Early Warning System for Mitigation of Geological Hazards," Bock will discuss the CRTN system and experiments conducted on a shake table at the Englekirk Structural Engineering Center at UC San Diego. The trials incorporated seismometer data from the 1994 magnitude-6.7 Northridge earthquake, a replay of the 2003 magnitude-8.3 Tokachi-Oki earthquake off Hokkaido, Japan, and the recently simulated ShakeOut magnitude-7.8 earthquake on the southern portion of the San Andreas fault. This new study offers more accurate real-time measurements of earthquakes and other natural hazards into the early-warning system. (Thurs., Dec. 18, 1:40 p.m. · Moscone West 3009)
"Ours is the only operational system that uses real-time GPS information," said Bock. "By adding GPS data we can greatly improve existing early-warning systems using traditional seismic data, especially for large earthquakes." Bock and others have been researching GPS technology as a viable monitoring tool for nearly 10 years. The CRTN infrastructure is the first mature network in operation to support an early-warning system for earthquakes magnitude-6 and larger.
A report released earlier this year by a team of earthquake experts concluded that California has a 99-percent chance of experiencing a major earthquake sometime in the next 30 years. To plan for such a scenario, a magnitude-7.8 earthquake was recently simulated during the ShakeOut experiment, originating on the southernmost section of the San Andreas fault and rupturing northwestward. Bock's system demonstrated that a nearly one-minute warning could have been issued for the Los Angeles area, which would be particularly hard hit by such an event. Scripps researchers hope to expand the network's operation throughout California by adding new GPS stations, incorporating data from seismic networks and offering additional information available through a public-friendly web interface.
An early-warning system consists of three components - real-time detection, notification and modeling of the magnitude event and location. The Scripps research team is completing the last and most critical component - to provide magnitude and location in real-time - that will give researchers and emergency responders information on where seismic waves are traveling in the seconds to minutes after the event occurs.
Bock and colleagues also helped develop a similar early-warning system for tsunamis that occurred in Indonesia in November 2008.
IN23A-1073 · Tuesday, Dec. 16, 1:40 p.m. · Moscone South, Hall D
"Real World Example of a Hazard Warning System based on a Network of Autonomous High Rate, Low Latency GPS Sensors"
G43A-0642 · Thursday, Dec. 18, 1:40 p.m. · Moscone South, Hall D
California Real Time Network: Test Bed for Mitigation of Geological and Atmospheric Hazards within a Modern Data Portal Environment