HR: 0830h
AN: S51E-0084    [PDF]
TI: Strong Ground Motion and Liquefaction During the Chi-Chi Earthquake
AU: * Wong, A
EM: wongal@seismo.berkeley.edu
AF: Alexander Wong, University of California, Department of Earth and Planetary Science, College of Letters and Science, McCone Hall, Berkeley, CA 94720-4767
AU: Wang, C
EM: chiyuen@seismo.berkeley.edu
AF: Alexander Wong, University of California, Department of Earth and Planetary Science, College of Letters and Science, McCone Hall, Berkeley, CA 94720-4767
AU: Chi, W
EM: chi@seismo.berkeley.edu
AF: Alexander Wong, University of California, Department of Earth and Planetary Science, College of Letters and Science, McCone Hall, Berkeley, CA 94720-4767
AU: Dreger, D
EM: dreger@seismo.berkeley.edu
AF: Alexander Wong, University of California, Department of Earth and Planetary Science, College of Letters and Science, McCone Hall, Berkeley, CA 94720-4767
AB: Traditional methods of liquefaction risk assessment have focused largely on the evaluation of localized soil characteristics. While this method of risk assessment has proven to be fairly successful, it requires penetration tests or other means of determining the soil properties at a particular site. It would therefore be useful to develop a method to evaluate liquefaction risk in a region without requiring site-by-site measurements of soil properties. One approach to this problem is to examine the correlation between various properties of the ground motion at a site and the likelihood of liquefaction. The 1999 Chi-Chi earthquake in Taiwan offers a unique opportunity to study this relationship because the earthquake caused widespread liquefaction, and data from extensive networks of both seismographs and hydrological wells is available. Using a series of 1-D and 3-D models of the Chi-Chi earthquake, we simulate the ground motion at sites where liquefaction or pore pressure increases were observed. The resulting synthetic seismograms allow us to study which types of ground motion are most likely to cause liquefaction or pore pressure buildup. For the Chi-Chi earthquake, we have found that the correlation between pore pressure changes and the spectral ground acceleration at certain frequencies is stronger than the correlation between pore pressure changes and the peak ground acceleration. Preliminary results show significant differences between the synthetic seismograms and empirical seismograms at seismic stations near liquefaction sites. These differences may in part be caused by the inelastic behaviors of the nearby soils due to liquefaction. If true, this could be used as a method to detect liquefaction that does not have surface effects.
DE: 1829 Groundwater hydrology
DE: 7200 SEISMOLOGY
DE: 7212 Earthquake ground motions and engineering
DE: 7223 Seismic hazard assessment and prediction
DE: 9320 Asia
SC: Seismology [S]
MN: 2003 Fall Meeting