HR: 1340h
AN: T43B-1348    [Abstracts]
TI: Implications of Groundwater Level Changes Induced by Earthquakes
AU: * Chia, Y
EM: ypc@ntu.edu.tw
AF: National Taiwan University, No. 1, Sec. 4 Roosevelt Rd., Taipei, 10673, Taiwan
AU: Chiu, J J
EM: jjchiu@aec.gov.tw
AF: Atomic Energy Council, 80, Sec. 1, Chenggong Rd., 7th Fl., Yonghe, 23452, Taiwan
AU: Lee, T
EM: f91224208@ntu.edu.tw
AF: National Taiwan University, No. 1, Sec. 4 Roosevelt Rd., Taipei, 10673, Taiwan
AU: Horng, M
EM: a610010@ms1.wra.gov.tw
AF: Water Resources Agency, 41-2, Sec. 3, Hsin-yi Rd., Taipei, 10651, Taiwan
AB: Earthquake-related groundwater level changes have been monitored by a dense network of multiple-well stations in Taiwan. The coseismic water level changes vary in wells of different depths at most stations. The variation of coseismic changes in the vertical direction implies possible inconsistency between the observed water-level changes and the coseismic strains calculated from simple dislocation models. The recovery rate of coseismic changes after earthquakes decreases with depth, suggesting the importance of aquifer confinement in the recovery process. Well water level data recorded in the vicinity of the seismogenic fault during the 1999 M7.6 Chi- Chi earthquake provide a preliminary framework of regional distribution of coseismic changes. We found that the magnitude of coseismic change is associated with characteristics, rather than depth, of the aquifer. The coseismic change in the footwall of the ruptured segment of the fault was much greater than that of the unruptured segment, suggesting that fault displacement is a controlling factor in the abrupt change of pore pressure. Coseismic rise or fall correlates well with hypocentral distance in the vicinity of the ruptured fault. Poor correlation, however, is found for such changes further from the earthquake epicenter.
DE: 1835 Hydrogeophysics
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
DE: 8168 Stresses: general
SC: Tectonophysics [T]
MN: 2007 Fall Meeting