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Precise location of San Andreas Fault tremors near Cholame, California using seismometer clusters: Slip on the deep extension of the fault?
Author(s) -
Shelly David R.,
Ellsworth William L.,
Ryberg Trond,
Haberland Christian,
Fuis Gary S.,
Murphy Janice,
Nadeau Robert M.,
Bürgmann Roland
Publication year - 2009
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl036367
Subject(s) - seismology , geology , seismometer , slip (aerodynamics) , san andreas fault , subduction , crust , fault (geology) , fault trace , shear (geology) , geodesy , geophysics , petrology , physics , tectonics , thermodynamics
We examine a 24‐hour period of active San Andreas Fault (SAF) tremor and show that this tremor is largely composed of repeated similar events. Utilizing this similarity, we locate the subset of the tremor with waveforms similar to an identified low frequency earthquake (LFE) “master template,” located using P and S wave arrivals to be ∼26 km deep. To compensate for low signal‐to‐noise, we estimate event‐pair differential times at “clusters” of nearby stations rather than at single stations. We find that the locations form a near‐linear structure in map view, striking parallel to the SAF and near the surface trace. Therefore, we suggest that at least a portion of the tremor occurs on the deep extension of the fault, likely reflecting shear slip, similar to subduction zone tremor. If so, the SAF may extend to the base of the crust, ∼10 km below the deepest regular earthquakes on the fault.