Rapid Earthquake Data Integration Project
In northern California, the BSL and the USGS Menlo Park collaborate to provide the timely and reliable earthquake information to the federal, state, and local governments, to public and private agencies, and to the general public. This joint earthquake notification system provides enhanced earthquake monitoring by building on the strengths of the Northern California Seismic Network (NCSN), operated by the USGS Menlo Park, and the Berkeley Digital Seismic Network (BDSN), operated by the UC Berkeley Seismological Laboratory.
Traditional efforts in earthquake monitoring and damage assessment have focused on basic research in earthquake phenomena in an "off-line" environment. That is, the research is generally conducted days, weeks, or months after the occurrence of an earthquake. However, recent technological advances now permit "real-time" analysis of events, yielding information on earthquake location, magnitude, rupture characteristics, and estimates of ground motion within minutes. Rapid access to these and other parameters will augment the capability of private and public agencies to respond to earthquake emergencies, aiding in the recovery of lifeline systems such as transportation, water, power, and communications.
On the USGS side, incoming analog data from the NCSN are digitized, picked, and associated as part of the Earthworm system. Preliminary locations, based on phase picks from the NCSN, are available within seconds, based on the association of a few arrivals, while final locations and preliminary coda magnitudes are available within 2-4 minutes. Earthworm reports events - both the "quick-look" 25 station hypocenters (without magnitudes) and the more final solutions (with magnitudes) to the Earlybird alarm module in Menlo Park. This system sends the Hypoinverse archive file to the BSL for additional processing, generates pages to USGS and UC Berkeley personnel, and updates the northern California earthquake WWW server. The Earthworm system also processes USGS strong-motion seismograms to determine peak ground motion parameters for use in the generation of "Shake Maps."
On the UC Berkeley side, the Hypoinverse archive file is used to drive the REDI processing system. This is a modification of the original REDI design, which identified and located events using raw phase data from the BDSN and NCSN. In the revised REDI processing, waveform data are processed to determine local magnitude, estimate peak ground motions, and obtain the seismic moment tensor and moment magnitude.
Recent additions to the REDI system include modules to determine faulting parameters such as the length and width of the rupture as well as the distribution of slip. These parameters are used to predict ground motions and provide updated maps of strong ground shaking.
Development of the REDI Project at UC Berkeley is supported by the Berkeley Seismological Laboratory, the USGS, and the California Office of Emergency Services.