In late 2003, the CISN experienced the first significant test of its capabilities with the M6.5 San Simeon earthquake. A brief 9 months later, an M6.0 earthquake occurred along the San Andreas fault in Parkfield, California.
Overall, the CISN performance for the distribution of information following the San Simeon and Parkfield earthquakes were good. Automatic information about the location was available within 30 seconds and a final location with a reliable magnitude was released about 4.5 minutes after the event. The first ShakeMap was issued 8 minutes after origin time and distributed to OES and multiple Web servers. During the next 24 hours, additional information about aftershock probabilities, the fault rupture, and seismological/engineering aspects of interest were made available by the CISN.
Unlike San Simeon, the Parkfield earthquake occurred during a weekday in a densely instrumented area of the Northern California network (although much of that instrumentation was analog). Like San Simeon, however, the earthquake illustrated some issues with CISN operations. For example, some difficulties were encountered with rarely exercised software, some clients were unhappy with the number of earthquake notifications received, firewalls (both within the CISN and with CISN client) continue to be problematic, and some aspects of the human response showed a lack of familiarity with appropriate procedures.
More information about the Parkfield earthquake is available in Chapter 13 in research contributions.
Berkeley Seismological Laboratory
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