Basic Characteristics of Geohazards Induced by Lushan Earthquake and Compare to Them of Wenchuan Earthquake

At 8∶02on April 20,2013,Ms7.0earthquake happened in Lushan county(30.3°N,103.0°E),Yaan,in Sichuan province,where located on the Longmenshan fault zone in eastern Tibet Plateau.In this paper,the basic characteristics,their forming mechanisms and typical cases of geohazards induced by4·20Lushan earthquake were analyzed,and with comparison on the differences of5·12Wenchuan earthquake,then the relationships between geohazards and magnitude,fault nature of activities,geomorphology,slope angle,seismic intensity in the two earthquakes area.Some conclusions are as follows:①There are four categories of geohazards induced by Lushan earthquake,landslides,collapse(rolling stones),debris flows and unstable slopes,and comparing to Wenchuan earthquake area,lower number,smaller scale and volume of shallow landslides or collapses,mainly concentrated in high alpine valleys and steep slope areas.②There are very similar characteristics and topography pregnant disaster conditions between the Lengmugou gullies in Baoxing County of Lushan earthquake zone and Sanyanyu gullies in Zhouqu County,2010,where affected by Wenchuan earthquake in 2008.③There are four types of forming mechanisms of geohazards induced by Lushan earthquake,they are cracking-rockslidescollision-scraping and then debris flows,cracking-rockslides,vibration-rainfall-rockslides-landslide and then debris flow,vibration-throwing or scrolling. Many hazards controlled by the coupling effect mechanism of endogenic and exogenic geological processes after earthquakes.④ Because of the differences of magnitude,fault nature of activities,geomorphology,topography,the geohazards induced by these two earthquakes are represented obvious similarities and differences,the type of disasters are same and the numbers,scales and volumes,casualties are significant different.