Precise tremor source locations and amplitude variations along the lower-crustal central San Andreas Fault

Shelly, David R.; Hardebeck, Jeanne L.

Abstract:

We precisely locate 88 tremor families along the central San Andreas Fault using a 3D velocity model and numerous P and S wave arrival times estimated from seismogram stacks of up to 400 events per tremor family. Maximum tremor amplitudes vary along the fault by at least a factor of 7, with by far the strongest sources along a 25 km section of the fault southeast of Parkfield. We also identify many weaker tremor families, which have largely escaped prior detection. Together, these sources extend 150 km along the fault, beneath creeping, transitional, and locked sections of the upper crustal fault. Depths are mostly between 18 and 28 km, in the lower crust. Epicenters are concentrated within 3 km of the surface trace, implying a nearly vertical fault. A prominent gap in detectible activity is located directly beneath the region of maximum slip in the 2004 magnitude 6.0 Parkfield earthquake.

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Article

ProdID:

70042290

Citation Author:

Shelly, David R.; Hardebeck, Jeanne L.

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Earthquake Science Center

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English

Citation Larger Work Title:

Geophysical Research Letters

Citation LatN:

42.0

Citation LatS:

32.5

Citation LonE:

-114.1

Citation LonW:

-124.4

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Citation Phsyical Description:

L14301

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AGU

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Citation Search Results Text:

Precise tremor source locations and amplitude variations along the lower-crustal central San Andreas Fault; 2010; Article; Journal; Geophysical Research Letters; Shelly, David R.; Hardebeck, Jeanne L.