Geotechnical and geological effects of the 21 September 1999 Chi-Chi earthquake, Taiwan

When the Chi-Chi earthquake ripped through the pitch dark of the very early morning hours of 21 September 1999, a large area was affected by various geotechnical and geological hazards in addition to the strong ground motion in central Taiwan. The epicenter of the earthquake was located in the central mountains of the island and rupture occurred on the Chelungpu fault. This is a North-South trending thrust fault with a dip of about 30 degrees to the east according to a 1999 US Geological Survey report authored by M. G. Bonilla. Taiwanese authorities had not believed this fault to be an active one because of the lack of evidence of fault activity during the Holocene age (during the last 11000 years). The earthquake hazards, other than strong ground shaking, included surface fault rupture, landsliding and liquefaction. Copyright (C) 2000 John Wiley & Sons, Ltd.