Applications for New Real-time Seismic Information: The TriNet Project in Southern California

Abstract

Historically, California's seismic networks have contributed to emergency response efforts after major earthquakes and provided, within the limits of available technology, rapid information on seismic activity. Since the late 1980's, the information generated by the networks has included magnitude, location, identification of the fault that ruptured, and, more recently, assessment of the probability of damaging aftershocks. While useful, this information was not sufficient to support critical postearthquake emergency management decision-making. With the implementation of TriNet in 1997, this situation has changed in southern California. In a post-Northridge assessment of seismic network performance, scientists concluded that use of new digital broadband sensors, modern data communications methods, and advanced computing could greatly improve the accuracy and timeliness of seismic information and provide useful decision-support tools for emergency responders. In the months that followed Northridge, seismologists responsible for network operations assembled a proposal detailing the necessary steps to develop a state-of-the-art broadband and strong-motion network that would reliably serve the needs of emergency management and those of scientific investigation and building code development (Hauksson et al., 2001; Goltz and Hauksson, 2001). The TriNet project was initiated in 1997 by three institutions: the California Institute of Technology, the California Geological Survey (formerly the California Division of Mines and Geology), and the United States Geological Survey. The five-year effort to build a state-of-the-art digital seismic and strong-motion network was supported by a Hazard Mitigation Grant (HMGP) of $20.8 million with funding provided by the Federal Emergency Management Agency through the California Governor's Office of Emergency Services. Because of provisions of the HMGP that tied funding of the project to the Northridge earthquake recovery, funds could be spent only for network enhancement in southern California. The Caltech outreach component (the California Geological Survey sponsored its own outreach program targeting the engineering community) of TriNet …