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Abstract On May 12，2008 at 14：28(local time)，a catastrophic earthquake with surface wave magnitude of 8.0 struck the Sichuan Province of China. Tens of thousands of landslides were triggered by this earthquake over a broad area. 48 007 landslides were interpreted from aerial photographs and multi-source remote sensing imageries，and they are verified by field investigation. Based on the interpretation results，landslide triggering factors with certainty analysis is carried out by means of GIS spatial analysis. The 12 impact factors contributing to the Wenchuan earthquake-induced landslide occurrences include stratigraphic，lithology，main faults，seismic intensity，macroscopic epicenter，surface rupture points，slope gradient，aspect，profile curvature，elevation，drainages，and roads. The certainty factor analysis result shows that five categories of high landslide susceptibility value are as follows：(1) stratigraphic of Cambrian，Ordovician，Permian and Carboniferous，lithology of intrusive rock group and limestone rock group；(2) Wenchuan earthquake-induced landslides are most affected by the main central fault，and also controlled by the Qianshan fault，the little impact for Houshan fault；(3) there are correlations between landslide susceptibility and seismic intensity，distance from the epicenter and surface rupture zone；(4) slope gradient of more than 40°，aspects of east and southeast directions，elevations between 1 000 m and 2 000 m，especial between 1 000 m and 1 500 m were susceptible for landslide occurrence；and (5) distance to drainages is less than 400 m and less than 2 000 m away from roads. The results show that the numerical intervals of each factor are inclined to landslides. This work is the basement for further study of earthquake- induced landslides hazard evaluation and prediction.
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Received: 24 February 2009
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