Research on the distribution characteristics of secondary geological disasters induced by 5.12 earthquake in Wenchuan county based on RS and GIS

摘要

Field observation, remote sensing combined with GIS technique were adopted to analysis the spatial distribution characteristics of secondary geological disasters induced by Wenchuan earthquake. The study results show that: (1) The earthquake-damaged slash mostly distributed in the two sides of main fault zones, earthquake-affected areas and disaster density decreased with the increase of distance from the main fault. (2) The earthquake-damaged slash mostly distributed in seismic intensity of IX and above. The region with greater seismic intensity had larger disaster density. Collapse and landslide distributed in high seismic intensity zone. (3) Hard rocks were easily caused secondary geological disasters by seismic waves. (4) The earthquake damaged slash mostly distributed within 0.5 km away from the river and decreased with the increase of distance from river. Collapse and landslide often appear at valley and the steep slope which more than 40 degree. The biggest hazard density appeared at altitude between 2000 m and 2500 m.