Large quantities of secondary geological hazards such as rock falls

landslide as well as debris flows were triggered by a magnitude 8.0 earthquake of Wenchuan

Sichuan

China. The identification of about 46560 secondary geological hazards through visual interpretation of multi-source remote sensing data over 14 counties in heavy disaster region after the overall remote sensing data were obtained. Their location and area information was input into GIS database. The distribution map

dot destiny map

histogram of number

total area

average area

area ratio

frequency of secondary geological hazards in 14 counties were drawn. Four regions of intensive geological hazards were identified. It is shown that there is a corresponding relation between the distribution of secondary geological hazards and the main faults. At last

the relation between the distribution and elevation

slope angle and intensity of earthquake triggered geological hazards were established. About 54.00 percent of secondary geological hazards in the study area occurred between altitude of 1000m and 2000m; about 62.42 percents of secondary geo- logical hazards occurred between slope angle of 30° and 50°; about 90.94 percents of secondary geological hazards occurred between Ⅺ and Ⅷ intensity. This paper provides an important database of secondary geological hazards triggered by Wenchuan Earthquake for further research on development trend

mechanism

prediction of secondary geological hazards

restoration and rebuilding

site selection

etc.