Overview of SMIP (Strong Motion Instrumentation Program) strong motion records from the Loma Prieta earthquake 17 October 1989
A total of 125 strong-motion records were recovered from 93 stations of the California Strong Motion Instrumentation Program (CSMIP). The 93 stations include 53 ground-response stations and 40 extensively instrumented structures. The most distant stations were approximately 175 km (105 miles) from the epicenter. Twenty-five records were obtained within 40 km (24 miles) of the epicenter. The closest SMIP station is Corralitos, located very close to the San Andreas fault and near the center of the aftershock zone. A peak horizontal acceleration of 65 percent g was recorded at this station. This is the first record from the nearfield of a magnitude 7 earthquake in California. Three other stations, Santa Cruz, Capitola, and Watsonville, within 20 km (12 miles) of the epicenter, recorded the shaking in the heavily damaged coastal area. Peak horizontal accelerations ranged from 40 percent g at Watsonville to 54 percent g at Capitola. All four of these stations recorded high vertical accelerations ranging from 40 percent g at Santa Cruz to 60 percent g at Capitola. Nine SMIP stations recorded the ground motion in the City of San Francisco with peak horizontal accelerations ranging from 9 percent to 21 percent g. Stations located on Yerba Buena Island and Treasure Island form a rock/soil pair that recorded peak horizontal accelerations of 6 percent and 16 percent g, respectively. In Oakland two stations recorded the ground motion of 26 percent and 29 percent g suggesting a similar level of shaking at the I-880 Freeway and at the east end of the damaged San Francisco-Oakland Bay Bridge.
- OSTI ID:
- 6225252
- Journal Information:
- California Geology (California Division of Mines and Geology); (USA), Vol. 43:2; ISSN 0026-4555
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CALIFORNIA
EARTHQUAKES
DATA ANALYSIS
AFTERSHOCKS
EARTHQUAKE MAGNITUDE
EPICENTERS
EVALUATION
GEOLOGIC FAULTS
GROUND MOTION
SEISMIC ARRAYS
SEISMIC EVENTS
SEISMIC WAVES
FEDERAL REGION IX
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
MEASURING INSTRUMENTS
MOTION
NORTH AMERICA
USA
580000* - Geosciences