| Abstract: | We analyze seismic data from the San Andreas Fault (SAF) near Parkfield, California, to test for annual modulation in seismicity rates. We use statistical analyses to show that seismicity is modulated with an annual period in the creeping section of the fault and a semiannual period in the locked section of the fault. Although the exact mechanism for seasonal triggering is undetermined, it appears that stresses associated with the hydrologic cycle are sufficient to fracture critically stressed rocks either through pore-pressure diffusion or crustal loading/ unloading. These results shed additional light on the state of stress along the SAF, indicating that hydrologically induced stress perturbations of ???2 kPa may be sufficient to trigger earthquakes. |
| Genre: | Article |
| ProdID: | 70032933 |
| Citation Author: | Christiansen, L. B.; Hurwitz, S.; Ingebritsen, S. E. |
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| Citation Issue: | 4 |
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| Citation Language: | English |
| Citation Larger Work Title: | Geophysical Research Letters |
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| Citation Search Results Text: | Annual modulation of seismicity along the San Andreas Fault near Parkfield, CA; 2007; Article; Journal; Geophysical Research Letters; Christiansen, L. B.; Hurwitz, S.; Ingebritsen, S. E. |
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| Citation Volume: | 34 |
| Citation Year: | 2007 |
| Type: | citation/reference |
| Text: | Annual modulation of seismicity along the San Andreas Fault near Parkfield, CA; 2007; Article; Journal; Geophysical Research Letters; Christiansen, L. B.; Hurwitz, S.; Ingebritsen, S. E. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1029/2006GL028634 |
| Date Other: | Mon, 1 Jan 2007 00:00 -0600 |
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