2013年甘肃岷县漳县6.6级地震触发滑坡及其构造分析

LANDSLIDES TRIGGERED BY THE 2013 MINXIAN-ZHANGXIAN,GANSU PROVINCE M_S6.6 EARTHQUAKE AND ITS TECTONIC ANALYSES

2013年7月22日,甘肃省岷县漳县交界发生了M S6.6地震。地震触发了大量的、类型各种各样的滑坡。滑坡类型以黄土崖崩、滑、倾为主,还有一些深层连贯型土质滑坡、大型土质流滑、斜坡裂缝等类型。地震滑坡主要分布在一个与临潭-宕昌断裂平行的长条形区域内。该长条形区域面积约为250km2,长度约40km,最大宽度约8km。对应不同构造段落的区域内滑坡发育程度不同,反映了不同段落发震构造的特征差异。滑坡的主体分布范围与震中位置表明了构造破裂是从SEE向NWW方向发展的。最后,分析了该滑坡主体分布区中心线与临潭-宕昌断裂在空间地理位置上相差10km的2种可能的原因。

On July 22,2013, an earthquake of Ms 6.6 occurred at the boundary between Minxian County and Zhangxian County,Gansu Province of China. Many landslides were triggered by the earthquake and the landslides were of various types, mainly in fails, slides, and topples occurring on loess cliffs, and also including soil deep-seated coherent landslides, large-scale soil avalanches, and slopes with cracks. Most of the landslides were distributed in an elongated area of 250km2 , parallels to the Lintan- Dangchang Fault, with about 40kin in length and the largest width of 8km. Landslides occurrence shows obvious difference along the central line of the elongated area, corresponding to different charac- teristics of different segments of the seismogenic fault. The elongated landslides main distribution area and the location of the epicenter indicate that the direction of the fault rupture propagation is from southeast-east to northwest-west. Finally,two probable reasons causing the horizontal distance of about 10kin between the central line of the elongated area and the Lintan-Dangchang Fault are presented.