The elevation containing 50% and 75% of mountain summits in the
Sinwulu catchment is 1831 m and 2746 m. The elevation distribution
of landsliding illustrates that the top elevations containing 50% and
75% of landslides became raised after typhoon Bilis and Mindulle, the
first heavy typhoon after the Chi-Chi earthquake and the Chengkung
earthquake, respectively (Table 4). Obviously, the top elevations
containing 50% of landslides are higher than the catchment-scale
topography. At the same time, the top elevations containing 75% of
landslides are closer to the elevation containing 75% of mountain
summits. This indicates that more than half of landsliding is close to
the mountain summits, especially after earthquakes. The seismic
disturbances make the scarps of landslides tend toward the summit of
mountain, which is in agreement with the expanding effect of seismic
wave on mountain tops (Geli et al., 1988).