川滇地区典型强震诱发滑坡分布对比研究

近年来，川滇地区相继发生了2008年汶川M_s 8.0级地震、2013年芦山M_s 7.0级地震、2014年鲁甸M_s 6.5级地震以及2017年九寨沟M_s7.0级地震，4次地震均引发了大量的地震滑坡灾害。通过统计分析，从地震、地形地貌和地质3个大类因素中，选取地面峰值加速度(ground peak acceleration, PGA)、地震烈度、距断层距离、地层岩性、高程、坡度、坡向7个因子，对比分析此4次强震诱发滑坡分布规律。研究发现它们存在共性特征：(1)4次地震均呈现出滑坡分布(数量和密度)与PGA和震级的正相关关系；(2)地质地貌越复杂地区(沟谷发育、坡降大)滑坡数量越多；(3)滑坡分布最大距离随地震震级增加而增加。此外，也发现了差异性特征：(1)在最大影响距离0.2倍的近断层区域，汶川地震滑坡占76%,而其他3次地震仅占27%;(2)滑坡在相对软弱地层(第四系地层、软层等)分布数量反而较硬岩区滑坡分布最少。针对差异性，从发震断裂性质、震级、地层岩性、地震烈度、断层错动方向讨论了成因。

Comparative study on the distribution of typical strong earthquake-induced landslides in Sichuan and Yunnan regions

In recent years, the Sichuan-Yunnan region has successively occurred the 2008 Wenchuan Ms8.0 earthquake, the 2013 Lushan Ms7.0 earthquake, the 2014 Ludian Ms6.5 earthquake and the 2017 Jiuzhaigou Ms7.0 earthquake, all of which caused a large number of earthquake landslide disasters. Through statistical analysis, seven factors, namely ground peak acceleration (PGA), seismic intensity, fault distance, stratigraphic lithology, elevation, slope and aspect, were selected from three major factors of earthquake, topography and geology, and the distribution law of landslide induced by these four strong earthquakes was compared and analyzed, and some common features were found. The four earthquakes showed a positive correlation between landslide distribution (number and density) and PGA and magnitude. The more complex geological landforms (gully development, large slopes) the more landslides. The maximum distance of landslide distribution increased with the increase of earthquake magnitude. In addition, difference characteristics were found. In the near fault area with a maximum impact distance of 0.2 times, Wenchuan seismic landslides accounted for 76%, while the other three earthquakes accounted for only 27%. Landslides were distributed in relatively weak strata (Quaternary strata, soft strata, etc.) and had the least distribution of landslides in hard rock areas. In view of the differences, the causes were discussed from the properties of seismic faults, magnitude, stratigraphic lithology, seismic intensity, and fault misalignment direction.