| Abstract: | Large sustained well water level changes (>10 cm) in response to distant (more than hundreds of kilometers) earthquakes have proven enigmatic for over 30 years. Here we use high sampling rates at a well near Grants Pass, Oregon, to perform the first simultaneous analysis of both the dynamic response of water level and sustained changes, or steps. We observe a factor of 40 increase in the ratio of water level amplitude to seismic wave ground velocity during a sudden coseismic step. On the basis of this observation we propose a new model for coseismic pore pressure steps in which a temporary barrier deposited by groundwater flow is entrained and removed by the more rapid flow induced by the seismic waves. In hydrothermal areas, this mechanism could lead to 4 ?? 10-2 MPa pressure changes and triggered seismicity. |
| Genre: | Article |
| ProdID: | 70025130 |
| Citation Author: | Brodsky, E. E.; Roeloffs, E.; Woodcock, D.; Gall, I.; Manga, M. |
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| Citation Issue: | 8 |
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| Citation Language: | English |
| Citation Larger Work Title: | Journal of Geophysical Research B: Solid Earth |
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| Citation Search Results Text: | A mechanism for sustained groundwater pressure changes induced by distant earthquakes; 2003; Article; Journal; Journal of Geophysical Research B: Solid Earth; Brodsky, E. E.; Roeloffs, E.; Woodcock, D.; Gall, I.; Manga, M. |
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| Citation Volume: | 108 |
| Citation Year: | 2003 |
| Type: | citation/reference |
| Text: | A mechanism for sustained groundwater pressure changes induced by distant earthquakes; 2003; Article; Journal; Journal of Geophysical Research B: Solid Earth; Brodsky, E. E.; Roeloffs, E.; Woodcock, D.; Gall, I.; Manga, M. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Wed, 1 Jan 2003 00:00 -0600 |
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