A Preliminary Report on the Landslides and Other Ground Surface Movements Induced by 1999 Chichi Earthquake, Taiwan

Preliminary discussion on the geomorphological conditions of characteristic ground surface movements induced by the 1999 Chichi Earthquake is presented on the basis of the field reconnaissance study in December, 1999.The displacement of the soft ground by the earthquake‐inducing fault was dominated by the horizontal movement and induced damage of structures. Two gigantic landslides visited in this study suggest that the dip of the intercalated mudstone and sandstone of the Neogene and the groundwater conditions determined the occurrence of large‐scale landslides.Extensive occurrence of surficial landslides suggests the importance of the weathering characteristics of coarse sedimentary formation of weak cohesion.