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Triggered tremor at San Andreas Fault near Parkfield

I also study tremor at San Andreas Fault (SAF), particularly those are triggered by large teleseismic earthquakes. I examine pulses of tremor activities near Parkfield ignited by the passing seismic waves from the great 2004 Mw 9.2 Sumatra event [Ghosh et al., 2009]. The prolonged shaking reveals very rich, and varied observations of dynamically-triggered tremor. Long period Love waves show the clearest evidence of tremor modulation. Based on the relationship between induced stress and tremor modulation, I show that tremor is consistent with shear slip on the fault plane. Interestingly, some tremor bursts appear to be associated with the passage of teleseismic P waves, which is unusual and surprising given the small stress they impart. In this work, I presented a detail analyses of tremor response due to the dynamic stressing from various body and surface waves. The figure shows seismograms of teleseismic waves and associated tremor at SAF near Parkfield.

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