In this paper, we study the mechanical process of
the Jiufengershan landslide, which is one of the major
slides triggered by Chi-Chi earthquake. This landslide
is located about 12 km to the north of the epicenter
(120.848E, 23.968N). The slide affected weathered,
jointed rock and soil materials, which slid along the
bedding plane, generating a rock-and-soil avalanche
during the earthquake. The volume of the sliding
debris is roughly 50106 m3 and consists of ~50–
60 m of thick-bedded muddy sandstones with thin
shale beds, covered by weathered rock and soil.
These materials were transported downslope for
about 1 km. The avalanche created a debris deposit
with maximum thickness of 110 m, which dammed
two small rivers and created three small lakes located
upstream.