“4·20”芦山地震地质灾害遥感快速解译与空间分析

摘要

2013年4月20日四川省芦山县发生7.0级地震,地震诱发了大量的崩塌滑坡.利用四川省测绘地理信息局和四川省地质调查院提供的芦山县城、太平镇、宝盛乡、龙门乡、清仁乡、上里镇、思延乡等重灾乡镇的震后高精度航空影像进行了地震灾害体的解译,利用GIS分析了芦山地震诱发的崩塌滑坡的空间分布关系和特征.结果表明崩塌滑坡主要受断层控制,距离发震断层3 km范围内分布密度最大；坡度是影响崩滑分布的重要因素,崩滑体主要分布在坡度40°～50°范围内；在海拔高度1～1.5 km范围内崩塌滑坡密度最大；距水系400m范围内的崩塌滑坡分布密度最大；白垩系泥岩、砂岩出露的地方容易产生大量崩塌滑坡；崩塌滑坡主要集中分布在Ⅸ烈度区.%A strong earthquake occurred in Lushan County,Sichuan Province on April 20,2013.It induced a large number of geohazards.These geohazards have had significant impacts on the earthquake region.In order to understand the distribution patterns of the co-seismic landslides,this paper makes an emergency interpretation and analysis of the post-earthquake airphotos of the landslides.The study areas cover Lushan,Taiping,Baosheng,Longmen,Qingren,Shangli and Siyan.The airphoto data were provided by Sichuan Bureau of Survey and Sichuan Institute of Geological Survey.The data indicate that the spatial distribution of the earthquake triggered landslides is dominated by the seismogenic fault in the GIS statistic analysis.The landslides are mainly distributed in the range of 3 km.The slope gradient was one of the main controlling factors of the landslide distribution,for most landslides occur in the range of 40°～ 50° slope gradient; Most landslides occur in the range of 1.0～ 1.5 km elevation above sea-level.Within the scope of 400 m from the drainage system,the landslides distribution density is the largest.Many landslides mainly occur in the soft rocks such as mudstone and sandstone,where small landslides likely occur.Most landslides mainly concentrate in Ⅸ intensity area.