This study has been done with the view of clarifying some characters of collapse occurred in the granite mountains by heavy rain fall, in relation to the topographical and geological features.
From the genetic point of view, these collapse are classified into the following six types.
(1) Landslide closely related to the rock joints.
The character of this type are that occur mainly at foot of slope composed of weathered granodiorite.
(2) Landslide of upper most layer on the vegetation slope.
It arise from difference of physical properties to the water between upper most layer and its basement rock. This landslide occur mainly on the slope composed of weathered biotite granite.
(3) Landslide possessed both characters, (1) and (2), together.
(4) Landslide closely related to the dykes intruded to granite.
(5) Landslide or landcreep occurred in the fault brecciated zone.
(6) Landslide or landcreep occurred in the talus deposits. The great part of collapse occurred in the granite mountains are the type (1), (2) and (3).