| Abstract: | The big bend segment of the San Andreas fault is the 300-km-long segment in southern California that strikes about N65??W, roughly 25?? counterclockwise from the local tangent to the small circle about the Pacific-North America pole of rotation. The broad distribution of deformation of trilateration networks along this segment implies a locking depth of at least 25 km as interpreted by the conventional model of strain accumulation (continuous slip on the fault below the locking depth at the rate of relative plate motion), whereas the observed seismicity and laboratory data on fault strength suggest that the locking depth should be no greater than 10 to 15 km. The discrepancy is explained by the viscoelastic coupling model which accounts for the viscoelastic response of the lower crust. Thus the broad distribution of deformation observed across the big bend segment can be largely associated with the San Andreas fault itself, not subsidiary faults distributed throughout the region. The Working Group on California Earthquake Probabilities [1995] in using geodetic data to estimate the seismic risk in southern California has assumed that strain accumulated off the San Andreas fault is released by earthquakes located off the San Andreas fault. Thus they count the San Andreas contribution to total seismic moment accumulation more than once, leading to an overestimate of the seismicity for magnitude 6 and greater earthquakes in their Type C zones. |
| Genre: | Article |
| ProdID: | 70021118 |
| Citation Author: | Savage, J. C.; Lisowski, M. |
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| Citation End Page: | 7292 |
| Citation Issue: | 4 |
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| Citation Language: | English |
| Citation Larger Work Title: | Journal of Geophysical Research B: Solid Earth |
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| Citation Number Of Pages: | 12 |
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| Citation Search Results Text: | Viscoelastic coupling model of the San Andreas fault along the big bend, southern California; 1997; Article; Journal; Journal of Geophysical Research B: Solid Earth; Savage, J. C.; Lisowski, M. |
| Citation Start Page: | 7281 |
| Citation Volume: | 103 |
| Citation Year: | 1997 |
| Type: | citation/reference |
| Text: | Viscoelastic coupling model of the San Andreas fault along the big bend, southern California; 1997; Article; Journal; Journal of Geophysical Research B: Solid Earth; Savage, J. C.; Lisowski, M. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Wed, 1 Jan 1997 00:00 -0600 |
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