Coseismic hydrologic response of an alluvial fan to the 1999 Chi-Chi earthquake, Taiwan
- 1Department of Earth and Planetary Science, University of California, Berkeley, California 94720, USA
- 2Water Resources Bureau, Taipei, Taiwan, Republic of China
- 3Institute of Earth Sciences, Academia Sinica Nankang, Taipei, Taiwan, Republic of China
Abstract
Widespread coseismic change in pore-water pressure across a large alluvial fan in central Taiwan in the 1999 Chi-Chi (Mw = 7.5) earthquake was captured for the first time by a dense network of hydrologic monitoring wells. The complex, yet systematic, pattern in the water-pressure change appears inconsistent with the existing models; it requires a model that is based on the nonlinear mechanical behavior of sediments under earthquake shaking. This paper presents direct field evidence that earthquake shaking causes rising pore pressure in alluvial fans, which in turn may lead to landslides, even on very gentle slopes.
Footnotes
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- Accepted May 18, 2001.
- Received January 5, 2001.
- Revision received May 1, 2001.
- Geological Society of America
