The Chi-Chi, Taiwan earthquake: Large surface displacements on an inland thrust fault



In the early morning (01:47 local time) of September 21, 1999, the largest earthquake of the century in Taiwan (Mw=7.6, ML=7.3) struck the central island near the small town of Chi-Chi. The hypocenter was located by the Central Weather Bureau Seismological Center at 23.87°N, 120.75°E, with a depth of about 7 km.

There were extensive surface ruptures for about 85 km along the Chelungpu fault with vertical thrust and left lateral strike-slip offsets. The maximum displacement of about 9.8 meters is among the largest fault movements ever measured for modern earthquakes. There was severe destruction in the towns of Chungliao, Nantou,Taichung, FengYuan, and Tungshi, with over 2300 fatalities and 8700 injuries.