ABSTRACT
This chapter examines rainfall-induced development of shallow landslides in Ta-Chia river watershed of central Taiwan. Several typhoon events have indicated that most shallow landslides in the study area occurred as a result of heavy rainfall and consequent pore pressure increases in the near subsurface. Taiwan is located in an active mountain belt created by the oblique collision between the northern Luzon arc and the Asian continental margin in which twothirds of this island is occupied by mountainous areas. An effective assessment of regional rainfall-induced landslides using 3S-based hydro-geological model was presented to investigate the most common shallow landslide in the Ta-Chia river watershed of central Taiwan. The landslide hazards were insignificant until the Chi-Chi earthquake hit the central Taiwan on September 21, 1999. The initial water table, hydrogeological properties and rainfall intensities for each grid were assigned by values according to its characteristics in space and time.
