Open Access

Effects of seismic ground motion and geological setting on the coseismic groundwater level changes caused by the 1999 Chi-Chi earthquake, Taiwan

  • Wen-Chi Lai13Email author,
  • Naoji Koizumi23,
  • Norio Matsumoto23,
  • Yuichi Kitagawa23,
  • Ching-Wee Lin13,
  • Chjeng-Lun Shieh13 and
  • Youe-Ping Lee33
Earth, Planets and Space201456:BF03352534

https://doi.org/10.1186/BF03352534

Received: 15 November 2002

Accepted: 14 July 2004

Published: 24 June 2014

Abstract

The groundwater level changes induced by the 1999 Chi-Chi earthquake were well recorded at the monitoring wells in and around the Choshui River alluvial fan, Taiwan, which is adjacent to the focal region. We analyzed the coseismic groundwater level changes related to the geological setting and seismic ground motion. In a typical fan area, the groundwater levels coseismically rose and those amplitudes increased as the ground acceleration and hydraulic conductivity became larger. In the slope area near the earthquake fault, the groundwater levels coseismically dropped and those amplitudes increased as the ground acceleration became larger. The liquefaction and permeability enhancement, whose degrees depend on the geological setting and seismic ground motion, might explain the characteristics of the coseismic groundwater level changes in the Choshui River alluvial fan.

Key words

Chi-Chi earthquakeliquefactiongeological settingground motionhydrologic conductivitypermeability enhancement