HR: 0800h
AN: H11D-0327 INVITED     [Abstracts]
TI: Using the response of streams to earthquakes to study hydrologic processes
AU: * Wang, C
EM: chiyuen@seismo.berkeley.edu
AF: Department of Earth and Planetary Science, University of California, Berkeley, CA 94720
AB: The hydrologic response of streams to earthquakes provides a way of probing hydrologic processes and properties at spatial and temporal scales that might otherwise be inaccessible. Significant increases in streamflow are commonly observed following large earthquakes. Analysis of the data from a dense network of stream gauges after the 1999 (Mw = 7.5) Chi-Chi earthquake in central Taiwan suggests that the excess water may have originated from the nearby mountains (Wang et al., 2004). On the other hand, analysis of data for liquefaction and streamflow reveals a striking similarity between the distance-to-liquefaction sites (Rliq) versus M relation and the distance-to-streamflow increases (Rstr) versus M relation, suggesting a causal relation between liquefaction and streamflow increase (Manga et al., 2003). I estimate the volume of water released during the Chi-Chi earthquake from liquefaction and compare this with that released from the nearby mountains. The comparison shows that, while the volume of water released from the nearby mountains was sufficient to supply the extra water in the streamflow increase, that released from liquefaction may fall significantly short to supply the required extra water. The similarity between the Rliq ~ M and the Rstr ~ M relations may simply reflect that the basic mechanisms that control the earthquake-induced streamflow also control the earthquake-induced liquefaction.
DE: 5114 Permeability and porosity
DE: 7212 Earthquake ground motions and engineering
DE: 1829 Groundwater hydrology
DE: 1836 Hydrologic budget (1655)
DE: 1860 Runoff and streamflow
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting