2014年8月云南鲁甸MS 6.5地震典型地表破裂特征

北京时间2014年8月3日16时30分，云南省鲁甸县发生了M_S 6.5地震，本次地震的发震构造为包谷垴-小河断裂。野外调查发现，王家坡不稳定斜坡上的地表破裂在整个破裂带中比较具有代表性，其地表破裂带整体走向N45°W-N50°W，并且由剪切破裂、张剪切破裂、压剪切破裂、张性破裂以及鼓包等典型地表破裂组成。其中左、右地表破裂边界与发震断层的出露位置一致，由断层错动造成；而部分地表破裂与断层的位置不重合，其成因分为2种，一种是发震断层导致的一些次级地表破裂，另一种是地震引发的滑坡后缘破裂。地表破裂类型和基本组合特征显示出王家坡潜在不稳定斜坡上的地表破裂带具有左旋走滑的性质。

Characteristics of Surface Rupture of the Ludian MS 6.5 Earthquake in Yunnan Province

At 16:30 on August 3, 2014, M_S 6.5 earthquake occurred in Ludian County, Yunnan Province, and the Baogunao-Xiaohe Fault is the causative structure of this earthquake. Through the field investigation, we found that the surface rupture on Wangjia slope is of typical characteristics of the earthquake, with the surface fracture zone overall trending N45°W-N50°W fracture zone and consisting of shear cracks, transtensional cracks, transpressional cracks, tension cracks and mole tracks. The boundary between the left and the right surface rupture is consistent with the location of the fault, and is caused by the fault movement. The partial surface rupture segment is not coincident with the location of the fault, which could be caused by the following two reasons. The first is that the seismogenic fault results in some secondary surface ruptures, and the second is that the seismogenic fault produces the earthquake landslide trailing edge fracture. The surface rupture types and basic characteristics indicate that the zone is characterized by left-lateral strike-slip mode.