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TriNet Provides New Tools for Rapid Earthquake Response By James D. Goltz, Seismological Laboratory, California Institute of Technology
Immediately following a damaging earthquake, emergency managers must make response decisions. Where are the major incidents? What resources must be mobilized and in what quantities? What areas have sustained damage and what areas are relatively free of damage? Will mutual aid be needed? Typically, first response organizations learn the answers to these questions through reconnaissance, police and fire services report from the stricken areas and information is gathered from other agencies. Organizations of the private sector must conduct their own reconnaissance and await reports from government regarding the status of regional infrastructure and services. Reconnaissance requires time, hours and sometimes days to complete and decisions regarding search and rescue, medical emergency response, mass care and shelter and other critical response needs must be made on the basis of available information. Often, this information is inadequate. Historically, the Southern California Seismic Network, operated by the California Institute of Technology and the United States Geological Survey, has contributed to reconnaissance efforts after a major earthquake and has provided, within the limits of available technology, rapid information on seismic activity in the region. The information generated by the network has included the magnitude, location, identification of the fault which ruptured and some assessment of the probability of damaging aftershocks. While useful, this information has not been sufficient to support rapid post-earthquake emergency management decision making. Since the Northridge earthquake, this situation has changed. Large earthquakes have an uncanny ability to find holes in our technologies and the January 17, 1994 earthquake did a masterful job. Basic earthquake information trickled from a seismic network hobbled by the inadequacies of older analog equipment, limited real-time telemetry and major software glitches. In short, information from the network was neither timely nor useful in the immediate post-impact period. But, in the months which followed Northridge, seismologists responsible for network operations assembled a proposal detailing the necessary steps to develop a state-of-the-art seismic network which would reliably serve the needs of emergency management as well as those of scientific investigation. In 1997, FEMA agreed to fund the project and TriNet was born. The TriNet project is named for the three organizations which have collaborated to build this network, the California Institute of Technology, the State of California Division of Mines and Geology, and the US Geological Survey. The five year project has a budget of approximately $20 million, which includes matching funds, and will conclude at the end of 2001. The TriNet budget is being spent for hardware, software development, telemetry and an active outreach program which seeks to move technology from the laboratory to the emergency operations center. The "real-time information products" from TriNet are, or will be, direct results of the new digital seismic network and include: the rapid broadcast of accurate and reliable information on magnitude, location and ground shaking for all earthquakes in the region; maps showing the distribution of ground motion expressed as intensity, peak acceleration, and velocity; and a pilot earthquake early warning system. TriNet will also provide input data for regional loss estimation software. The maps which display ground motion are particularly important for emergency management and merit some additional description. Known as ShakeMap and available on the web at http://www.trinet.org/shake.html, these maps offer an important increment of information beyond magnitude and location of the earthquake epicenter. By displaying the distribution of ground shaking within 5 minutes of the earthquake, emergency responders can rapidly assess what areas have been severely impacted and begin responding based on an accurate overall assessment of the scope of the disaster. In Northridge, like the 1989 Loma Prieta earthquake, some areas of heavy damage were quickly identified through ground and aerial reconnaissance but there were also relatively hidden pockets of severe damage that were belatedly discovered. These areas included Santa Cruz and Watsonville in 1989 and Santa Monica in 1994. ShakeMap will expose these areas quickly and delays in response can be avoided. In a very recent development, the rapid loss estimation software, used by the State Office of Emergency Services to calculate damage and population impacts in an earthquake, has been modified to utilize ground motion data from TriNet. The Early Post-Earthquake Damage Assessment Tool (EPEDAT) developed by EQE International, Inc. calculates estimates of economic loss in an earthquake and is expressed as total dollar loss and losses to structures and contents; damage in terms of the number of red and yellow tagged buildings, both residential and commercial; utility damage for water, power, and natural gas; and population impacts including the number of casualties and persons displaced from their homes. Prior to the use of TriNet ground motion data, EPEDAT attempted to estimate ground motion based on magnitude and location. Utilizing actual ground motion data will increase the accuracy of EPEDAT loss estimates. Perhaps the most intriguing of new technologies being developed through the TriNet project is a pilot earthquake early warning capability which will, for some earthquakes, provide a few seconds warning prior to the arrival of strong ground motion from an earthquake. An early warning system, if developed and fully deployed in the region, would have its greatest utility in very large earthquakes which begin in regions remote from population centers but generate very strong ground motion capable of causing casualties and damage over the entire region. Initial assessments suggest that even a few seconds warning of approaching danger would allow school children time to duck and cover, slow fast moving trains, open elevator doors, and alter other processes which could result in injury or damage if uninterrupted. These new developments hold great promise for improving emergency response after the next major earthquake we will experience in Southern California. The numerous small earthquakes which occur daily in California have provided TriNet scientists opportunities to test and calibrate the new system and ShakeMaps have been produced for earthquakes of magnitude 3.7 or greater for approximately one year. The TriNet project has wisely utilized the reservoir of experience held by the emergency services community as the project has proceeded and it is through the cooperative efforts of many disciplines that earthquakes will someday be reduced to natural phenomena rather than natural disasters. Bio James D. Goltz is Manager of the Office of Earthquake Programs at the California Institute of Technology and Chair of the TriNet Outreach Committee. His experience includes emergency planning, natural hazards research, consulting and technology transfer during a twenty year career.
Click here to see example of ShakeMap
ShakeMap Fact Sheet Description: ShakeMap is a web-based real-time map information product which displays ground shaking parameters for earthquakes of M=4 in southern California. Ground shaking is expressed as intensity, peak acceleration and peak velocity. ShakeMap is available on the Internet at http://www.trinet.org. Background: Maps of ground shaking following significant events, usually expressed in Modified Mercalli intensities (MMI), have been produced for many years. Typically, they require weeks and months to produce. These maps play an important role in the study of large earthquakes and in providing a common format for comparison of earthquakes around the world. Recent advances in real-time seismographic data acquisition and newly developed relationships between recorded ground motion parameters and estimated MMI have made it possible to produce "shake maps" in a few minutes following an earthquake. Current Status: Under the TriNet project, prototype shake maps have been generated for the last 12 months for earthquakes = M4 and are now posted on the TriNet website (http://www.trinet.org) within 5 minutes of occurrence. These maps express ground shaking as peak ground acceleration, peak velocity and as instrumental intensity. The installation of additional stations and real-time telemetry linking these stations with a central processing site have made real-time ground motion mapping a reality. Nevertheless, there remain gaps in station coverage so interpolation and estimation of ground motion parameters is necessary for mapping smaller earthquakes and those on the perimeter of the network. As station coverage improves, these problems will be alleviated. Future Plans: The potential utility of these maps for emergency management is tremendous. The distribution of shaking in a large earthquake, whether expressed as peak acceleration or intensity, provides responding organizations a significant increment of information beyond magnitude and epicentral location. Real-time ground shaking maps provide an immediate opportunity to assess the scope of an event, that is, to determine what areas were subject to the highest intensities and probable impacts as well as those which received only weak motions and are likely to be undamaged. These maps will certainly find additional utility in supporting decision making regarding mobilization of resources, mutual aid, damage assessment and aid to victims. ShakeMap may be provided to organizations with critical emergency response functions over a dedicated extranet web server to ensure access.
More Information:
Dr. David Wald, US Geological Survey, Pasadena, Telephone (626) 583-7238, wald@gps.caltech.edu	Mr. James Goltz, Caltech, Pasadena, telephone (626) 395-3298, jgoltz@gps.caltech.edu
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