鲜水河断裂带炉霍段地震滑坡空间分布规律分析

SPATIAL DISTRIBUTION ANALYSIS OF SEISMIC LANDSLIDES ALONG LUHUO SEGMENT OF XIANSHUIHE FAULT ZONE

鲜水河断裂带炉霍段具有极强的活动性，一旦发生地震，极有可能引发大量的滑坡等地质灾害。研究区发育1973年地震滑坡179个（通过现场调查识别出43个），1973年以前地震滑坡62个。本文研究数据基于1973年179个及1973年以前62个地震滑坡，共计241个地震滑坡。利用统计分析方法研究了1973年179个地震滑坡分布与烈度及震中距的关系，分析了241个地震滑坡发育的滑动方向、地层岩性、地形坡度、相对高程及在断裂不同位置的分布特征。结果显示：（1）炉霍断裂地震滑坡规模以小型为主；（2）集中于Ⅸ～Ⅹ度烈度区内；（3）距震中0～5km及10～15km范围内密度最大；（4）滑动方向多与断裂斜交，交角介于35＆#176;～75＆#176;；（5）断裂南东段滑坡数量多于北西段，北东盘多于南西盘，北西段的北东盘滑坡个体面积较大；（6）滑坡多发育于T2-3 r地层中；（7）主要分布于斜坡的中下部，相对高程主要介于30～60m；（8）发育坡度多介于30＆#176;～45＆#176;，具有规模越大，坡度越小的特点。

Massive landslides can be induced by earthquake because of the strong earthquake activity and fragile geological environment in Luhuo segment of the Xianshuihe fault zone.179 landslides in 1973 and 62 landslides before 1973 are obtained through data collection and geological investigation.This paper is based on the 62 landslides before 1973 and 179 landslides in 1973.It makes a statistical analysis of the characteristic parameters of Luhuo earthquake-triggered landslides in 1973 and before.Seven characteristic parameters of the seismic landslides are analyzed.They are seismic intensity,epicentral distance,slip direction,formation lithology,slope angle,height,distribution in NW part and SE part.This study supports the following views.（1）The most landslides have a small scale;（2）Seismic intensity zones are between Ⅸ and Ⅹ;（3）Epicentral distance between 0km to 5km and 10km to 15km are high-incidence zones;（4）Angle of slip direction and fault is between 35＆#176;and 75＆#176;;（5）Landslides in SE part of the fault is more than those in NW part.The NE foot of NW part has larger area;（6）Formation lithology that have the most landslides is T2-3 r;（7）Heights are between 30m to 60m.Major are distributed in the lower slope;（8）Slope angles are between 30＆#176;to 45＆#176;.The larger landslides always have lower angles.