CWB free-field strong-motion data from the 21 September Chi-Chi, Taiwan, earthquake

The Chi-Chi earthquake occurred at 17:47 on 20 September 1999 and is the largest earthquake (M_W 7.6) to have occurred on land in Taiwan in the twentieth century. This earthquake caused considerable damage and was named the “921 Chi-Chi Great Earthquake” by the Taiwan government, as the local date was 21 September. Because an extensive strong-motion instrumentation program in Taiwan was completed by the Central Weather Bureau (CWB) in 1996, over 30,000 digital strong-motion records have been obtained from the Chi-Chi earthquake and thousands of its aftershocks. These records form the largest set of strong-motion data recorded from a major earthquake since strong-motion seismology studies began in the 1930s. This data set is important to seismology and earthquake engineering because it includes over 60 recording sites within 20 km of the fault ruptures, which provides a five-fold increase of such near-field records available for the entire world.