The Ms 8.0 Wenchuan earthquake, whose epicenter was located
at 31.02N, 103.367E near Yingxiu town, has caused many kinds of
geological disasters and widely distributed building damages in a
large quake-hit area along the Yingxiu-Beichuan fault (Fig. 1).
Fig. 1 shows the 3D view of the study area, where a Landsat
ETM + image was superimposed on the SRTM DEM. Yingxiu town
and Beichuan county seat, two of the severest quake-hit areas,
were completely destroyed in Wenchuan earthquake (Fu et al.,
2009a,b). For Dujiangyan city, which is located on the boundary
of Longmenshan mountain range and Sichuan basin, only old
buildings were destroyed more severely. However, Sichuan basin
was less destroyed in Wenchuan earthquake. Landslides caused
by Wenchuan earthquake blocked the rivers in Longmenshan
mountain region, which resulted in many barrier lakes (Fu et al.,
2009b).