NEHRP Clearinghouse
- Title
- Principal Facts for Gravity Data Along the Hayward Fault and Vicinity, San Francisco Bay Area, Northern California.
- File
- PB2006105443.pdf
- Author(s)
- Ponce, D. A.
- Source
- January 2001, 32 p.
- Identifying Number(s)
- USGS/OFR-01-124
- Abstract
- The U.S. Geological Survey (USGS) established over 940 gravity stations along the Hayward fault and vicinity. The Hayward fault, regarded as one of the most hazardous faults in northern California (Working Group on California Earthquake Probabilities, 1999), extends for about 90 km from Fremont in the southeast to San Pablo Bay in the northwest. The Hayward fault is predominantly a right-lateral strike-slip fault that forms the western boundary of the East Bay Hills. These data and associated physical property measurement were collected as part of on-going studies to help determine the earthquake hazard potential of major faults within the San Francisco Bay region. Gravity data were collected between latitude 37 degrees 30' and 38 degrees 15' N and longitude 121 degreees 45' and 122 degrees 30' W. Gravity stations were located on the following 7.5 minute quadrangles: Newark, Niles, San Leandro, Hayward, Dublin, Oakland West, Oakland East, Las Trampas Ridge, Diablo, Richmond, Briones Valley, Walnut Creek, and Clayton. All data were ultimately tied to primary gravity base station Menlo Park A, located on the campus of the U.S. Geological Survey in Menlo Park, Calif. (latitude 37 degree 27.34' N, longitude 122 degrees 10.18' W, observed gravity value 979944.27 mGal).
- Keywords
- San Francisco Bay area; Isostatic gravity maps; Hayward Fault; Gravity; California; Sampling; Data collection; Topographic maps; Physical property data; Isostatic gravity anomalies; Rocks; Earthquakes