| Abstract: | Following the M(w) 6.7 Northridge earthquake, significant postseismic displacements were resolved with GPS. Using a three-dimensional viscoelastic model, we suggest that this deformation is mainly driven by viscous flow in the lower crust. Such flow can transfer stress to the upper crust and load the rupture zone of the main shock at a decaying rate. Most aftershocks within the rupture zone, especially those that occurred after the first several weeks of the main shock, may have been triggered by continuous stress loading from viscous flow. The long-term decay time of aftershocks (about 2 years) approximately matches the decay of viscoelastic loading, and thus is controlled by the viscosity of the lower crust. Our model provides a physical interpretation of the observed correlation between aftershock decay rate and surface heat flow.Following the Mw 6.7 Northridge earthquake, significant postseismic displacements were resolved with GPS. Using a three-dimensional viscoelastic model, we suggest that this deformation is mainly driven by viscous flow in the lower crust. Such flow can transfer stress to the upper crust and load the rupture zone of the main shock at a decaying rate. Most aftershocks within the rupture zone, especially those that occurred after the first several weeks of the main shock, may have been triggered by continuous stress loading from viscous flow. The long-term decay time of aftershocks (about 2 years) approximately matches the decay of viscoelastic loading, and thus is controlled by the viscosity of the lower crust. Our model provides a physical interpretation of the observed correlation between aftershock decay rate and surface heat flow. |
| Genre: | Article |
| ProdID: | 70021248 |
| Citation Author: | Deng, J.; Hudnut, K.; Gurnis, M.; Hauksson, E. |
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| Citation End Page: | 3212 |
| Citation Issue: | 21 |
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| Citation Language: | English |
| Citation Larger Work Title: | Geophysical Research Letters |
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| Citation Number Of Pages: | 4 |
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| Citation Publisher: | American Geophysical Union |
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| Citation Search Results Text: | Stress loading from viscous flow in the lower crust and triggering of aftershocks following the 1994 Northridge, California, earthquake; 1999; Article; Journal; Geophysical Research Letters; Deng, J.; Hudnut, K.; Gurnis, M.; Hauksson, E. |
| Citation Start Page: | 3209 |
| Citation Volume: | 26 |
| Citation Year: | 1999 |
| Type: | citation/reference |
| Text: | Stress loading from viscous flow in the lower crust and triggering of aftershocks following the 1994 Northridge, California, earthquake; 1999; Article; Journal; Geophysical Research Letters; Deng, J.; Hudnut, K.; Gurnis, M.; Hauksson, E. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1029/1999GL010496 |
| Date Other: | Fri, 1 Jan 1999 00:00 -0600 |
| Publisher: | American Geophysical Union |
