RELATIONSHIP BETWEEN DISTRIBUTION CHARACTERISTICS OF PREHISTORIC LANDSLIDES AND SEISMIC ACTIVITY ALONG QINLING PIEDMONT FAULT

Earthquake-induced landslides are serious secondary geological hazards,and they are also an important force to change the topography of the earth surface. Research on the scale,number,and type of earthquake-induced landslides is an important method for seismic risk assessment and the main method for understanding seismic geological disasters and approaches. The scale,quantity and the type of earthquake-induced landslide is an important way to evaluate the seismic risk,and also the main approach to understand the seismic hazard. There is a prehistoric landslide group of about 50 km long in the middle part of the northern foothills of the Qinling Mountains. It is distributed in parallel with the Qingling Piedmont fault. The recent research generally believes that the prehistoric landslide group was probably induced by the significance earthquake of the Qingling Piedmont fault activity. But there is no detailed study on the magnitude and influence range of this earthquake. In this paper,we use the high-resolution digital elevation model(DEM)that is produced from the ZY-3 satellite stereo image,and multispectral remote sensing image to mapping the landslide area in detail. Combined with the some field investigation,we finally obtain a detailed map of the prehistoric landslide distribution in the Qinling Piedmont area. In the end,totaling 43 prehistoric landslides are interpreted and concentrated in a area of 70×10 km². Based on the relationship between the moment magnitude and the frequency-area distribution(FAD) of inventories of triggered landslides,we analyze the earthquake scale of the prehistoric landslide group in Qinling Piedmont area. The magnitude of the earthquake that triggered the prehistoric landslide group in the north Qinling Piedmont should be between 7.6 and 8.1. By combining the regional seismic tectonic environment and the comparison with modern earthquake-induced landslide events,we conclude that the Qinling Piedmont fault has the potential to produce earthquakes of more than 7.5 magnitude. This research provides quantitative data support for understanding the causes of the prehistoric landslide group in the Qingling Piedmont area,and also has practical significance for understanding the seismic risk of the Qinling Piedmont fault.