为了研究芦山地震前后地质灾害在不同环境中的分布规律,对研究区震前3 814处和震后新增1 337处地质灾害与各环境因素的关系进行了统计和分析,得出以下结论:1.震后新增灾害数量的88.41%分布在距震中100km范围内,密度随距震中距离的增大而减小;新增灾害67.31%分布在地震烈度Ⅶ度及其以上地区,灾害密度随地震烈度减小而逐渐减小.2.震前和震后新增灾害数量和密度均随距河流距离的增大而减小.3.震前和新增地质灾害数量和密度在砂砾岩和花岗岩中较为发育.4.震后和新增灾害数量和密度均以海拔500~1 000m和1000~1 500m较大.5.震前和震后新增灾害总数的94.99%和91.85%发生在坡度小于40.的范围;震前灾害密度在随坡度增大逐渐减小,震后新增灾害密度随坡度变化规律不明显,其主要原因是震前灾害以滑坡为主,而震后新增灾害崩塌和滑坡数量相当.
For revealing the distribution of geohazards in environmental factors,3 814 geohazards before Lushan earthquake and 1 337 geohazards after Lushan earthquake were used to statistics and analysis the relationship between geohazards and environmental factors.The main results of the paper can be summarized as follows.(1)88.41% of geohazards after earthquake distributed in the range of 100 km from the epicenter and the density of geohazards decreased with the increase of distance from epicenter.About 67.31% of geohazards after earthquake distributed in area with or more than seismic intensity Ⅶ and the density of geohazards decreased with the increase of seismic intensity.(2) The amount and density of geohazards before earthquake and geohazards after earthquake all decreased with the increase of distance from rivers.(3) The amount and density of geohazards before earthquake and geohazards after earthquake were maximum in conglomerate and granite.(4) The amount and density of geohazards before earthquake and geohazards after earthquake were maximum in relief from 500 to 1 000 meters and 1 000 to 1 500 meters.(5) About 94.99% of geohazards before earthquake and 91.85% of geohazards after earthquake were in area where the slope was less than 40°.The density of geohazards before earthquake decreased with the increase of slope but the density of geohazards after earthquake did not changed obviously with the slope.