Source scaling telationships of microearthquakes at Parkfield, CA, determined using the SAFOD pilot hole seismic array

Kazutoshi Imanishi; William L. Ellsworth

doi:10.1029/170gm10

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Source scaling telationships of microearthquakes at Parkfield, CA, determined using the SAFOD pilot hole seismic array

Kazutoshi Imanishi·William L. Ellsworth

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Abstract

Weestimate thesourceparametersof34microearthquakes at Parkfield,CA,ranginginsizefromM-0.2 toM2.1, byanalyzingseismogramsrecorded bythe32-level, 3-componentseismic arrayinstalled in theSAFODPilotHole. Wesucceeded in obtainingstablespectral ratios by stacking theratioscalculatedfromthemovingwindowstakenalongtherecordfollowingthedirectwaves.Thesespectral ratios were modeledtodetermine seismicmoments andcornerfrequenciesassuming an omega-squared model. Static stress dropsand apparent stresses ofmicroearthquakes at Parkfielddisplay moment-independent scaling in agreementwith scaling lawsreported for moderate and large earthquakes. It is likely that thedynamics of microearthquakes at Parkfieldis macroscopicallysimilar to that oflarger tectonic earthquakes.

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Source-reported bounding extent: 35.88156581190162° to 35.912485263352764° latitude; -120.45467280913404° to -120.41440575948329° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Kazutoshi Imanishi, William L. Ellsworth. 2006. Source scaling telationships of microearthquakes at Parkfield, CA, determined using the SAFOD pilot hole seismic array. https://doi.org/10.1029/170gm10

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