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Seismometers record the motion of the earth in the frequency band from hundreds of seconds to hundreds of Hertz (Hz). Seismologists use these recordings to locate earthquakes, to measure their size, to determine the amount of ground shaking and to determine their rupture characteristics. In northern California, the UC Berkeley Seismological Laboratory and the USGS Menlo Park are among several organizations which operate a number of seismic instruments in the San Francisco Bay Area. Together, they form the Northern California Management Center of the California Integrated Seismic Network and are responsible for rapid reporting of earthquake information.

The Northern California Seismic Network (NCSN) is an array of seismometers in northern and central California operated by the USGS Menlo Park. The instrumentation is a mix of short-period vertical component sensors and strong motion accelerometers. The density of these instruments provides important information for locating earthquakes.

The Berkeley Digital Seismic Network (BDSN) is an array of high dynamic range, broadband seismometers in northern and central California, operated by the UC Berkeley Seismological Laboratory. These sensors provide important data for the reliable estimation of earthquake size and rupture characteristics.

The Hayward Fault Network (HFN) is an array of borehole seismometers and accelerometers for monitoring small earthquakes along the Hayward Fault operated by the UC Berkeley Seismological Laboratory and the USGS Menlo Park. The UC Berkeley portion of the Hayward fault network includes the Bridge Program, a collaborative venture among UC Berkeley, the USGS Menlo Park, Caltrans, Lawrence Livermore National Laboratory, Lawrence Berkeley Laboratory, the California Division of Mines and Geology, and the Earthquake Power Research Institute to monitor ground motions near Bay Area bridges. The borehole sensors are critical for the detection and location of small earthquakes, which would otherwise be unobserved in this high-noise, urban environment.

Information available from the seismic networks includes:

• Current maps of earthquakes in the Bay Area
• Weekly, monthly, and annual maps of earthquakes near the Hayward fault
• "Seismocams" from stations near the Hayward and Rodgers Creek Faults
  • Strawberry Canyon
  • Bollinger Canyon
  • Hamilton Field
• Memento Mori - a real-time seismic data display from the Hayward fault

Berkeley Seismological Laboratory
202 McCone Hall, UC Berkeley, Berkeley CA 94720-4760
Questions and comments to www@seismo.berkeley.edu
Copyright 2003, The Regents of the University of California.
Last modified: Wed Sep 17 09:20:44 PDT 2008