REMOTE SENSING RESEARCH ON DAGUANGBAO GIGANTIC ROCKSLIDE TRIGGERED BY WENCHUAN EARTHQUAKE

The Daguangbao gigantic rockslide is located on the Gaochuan village,Anxia county.It is the hugest landslide triggered by the Wenchuan 8.0 earthquake on May 12 of 2008.This paper uses four periods of remote sensing data with high resolution before/after the earthquake and ground surveying and mapping data to analyze the basic features of the Daguangbao rockslide.The basic features include the accumulation and movement zoning,the sliding surface and exiting,and the volume.The Daguangbao gigantic rockslide is classified into sliding source,back depression,main bedrock accumulation,down-stream accumulation,up-stream accumulation and front lobe.The main bedrock accumulation remained a structure of parent layered limestone rockmass with slight separation that is 1, 100m long, 490m wide, 215m average thick and 464millions m3 in the volume.The sliding direction and boundary are outlined according to the compared result before/after topography,geomorphology,and mining adit,waste ore material and sheds.The bedrock sliding distance is about 1750m.A digital elevation model with the scale of 1 to 5000 before/after earthquake is established to calculate the area and the thickness of the rockslide accumulation.With the AutoCAD,a 3D entity model of the sliding surface is also established.The result shows the whole Daguangbao gigantic rockslide is 4300m long, 3500m wide and 550m thick in the maximum.The debris volume is about 1.15~1.2 billion m3.It is the hugest landslide not only in China,but also in the world in recent hundred years.