| Moderately strong earthquakes in high mountains and valleys in western of our country will often trigger coseismic landslides,which will aggravate the economic losses and casualties caused by the earthquake to a certain extent.Therefore,from the perspective of earthquake case anatomy,remote sensing interpretation of spatial distribution of coearthquake landslide is carried out to provide valuable research results for the disaster-causing characteristics of typical earthquake disasters,and at the same time provide effective decision-making suggestions for post-disaster reconstruction and emergency rescue.On August 3,2014,a M_s6.5 magnitude earthquake occurred in Ludian County near Zhaotong City,Yunnan Province,causing 617 heavy casualties.After the earthquake,many scholars carried out emergency scientific investigations and continuous follow-up research on the seismogenic structure and secondary disasters of the earthquake.However,there is still no broad consensus on whether the Baogou-Xiaohe fault is the seismogenic structure of the earthquake and there is a need for further research on the types of landslide triggered by the earthquake.On the basis of previous studies,this paper takes Ludian earthquake landslide in2014 as the research object,and uses UAV aerial photography data,Google Earth archived data,comprehensive interpretation of high-resolution satellite remote sensing data,field actual investigation,ground-ground-radar profile observation and other technical means to retrospectively study the general characteristics of Ludian earthquake triggered landslide and the identification of seismogenic structure.The main conclusions are as follows:(1)Ground penetrating radar profile shows that the ground fractures at the rear edge of the Wangjiapo landslide are shallow fracture system controlled by limestone joint surface near the surface,belonging to the fracture zone on the canyon steep slope caused by strong vibration conditions.The fracture zone does not extend downward within 40 m below the surface,so the evidence for partial cracks as surface fractures is insufficient;(2)The Ludian earthquake triggered a total of 6 209 coseismic landslides with a total interpreted area of 9.72 km~2,among which 10 landslides with an area of～100 000 m~2 caused serious disasters such as the blockage of the Niulan River by weir and the interruption of lifeline.The main body of coseismic landslides was the collapse of bedrock.The collapse has the characteristics of small provenance area,narrow circulation area and inverted rock accumulation area,so the landslide area is not the actual area of the landslide;(3)The coseismic landslides triggered by the 2014 Ludian earthquake belonged to the main types of rock collapse and debris flow on the slope of broken bedrock.These types of landslides have been confirmed in many recent cases of moderate and strong earthquakes in western China.Therefore,in the study of coseismic landslide mapping,we should not only pay attention to the integrity of seismic landslide interpretation,but also pay attention to the geological background of landslide occurrence,so that the characteristics of earthquake landslide and the corresponding characteristics of disaster can be described more accurately. |
