The Chi-Chi earthquake is the largest inland earthquake in Taiwan during the 20th century. It caused severe damage in central Taiwan. Three possible induced earthquakes triggered by a mainshock are being examined from the strong ground motion data. The occurrence of these three-triggered events can be used to explain the difference between preliminary isoseismal map, based on the real-time data, and final one. They can also explain why a wide area of aftershock distribution was observed. ON the other hand, the overshooting of ground motion at those stations located near the northern end of Chelungpu fault is probably the reason for the complex surface rupture observed between Feng Yuan and TungShih.