景谷M_S6.6地震同震地表破坏特征与孕震构造

发布时间：2018-04-16 17:59

本文选题：景谷地震 + 无量山断裂带　；参考：《地球物理学报》2016年07期

【摘要】：无量山断裂带位于云南西南部,主要由磨黑、宁洱、普文和景谷—云仙4条断裂组成,晚第四纪活动特征明显.受青藏高原隆起影响滇西南块体向南运动,中下地壳广泛存在的低速层为块体运动提供了有利条件,但刚性的临沧花岗岩体对其南向运动起着顶托作用,使得东、西两侧块体运动速率出现差异,且块体运动方向与无量山断裂带呈小角度相交.在此背景下,无量山断裂带表现为水平右旋走滑运动,起着滑动分解应变的作用.在其与横向断层交汇部位或在断裂端部,应力易于集中而引发地震,此次MS6.6地震就发生在断裂的端部.据野外科考调查,在宏观震中区集中出现带状砂土液化和地裂缝等地面破坏.喷砂孔呈串珠状线性分布,主要有NW和NE两组;NW向地裂缝呈右阶雁行状、NE向地裂缝呈左阶雁行状排列特征,它们具有明显的构造成因.地震烈度长轴方向、余震分布和震源机制解等显示,此次地震是沿NW向节面右旋走滑所致,宏观地面破坏特征和微观观测结果非常吻合,一致表明此次地震破裂与景谷—云仙断裂运动有关,其孕震构造应是景谷—云仙断裂.
[Abstract]:Located in the southwest of Yunnan Wuliang Mountain fault zone is mainly composed of Mohei, Ninger, Jinggu Yunxian and Puwen consists of 4 faults, late Quaternary activity characteristics. By the influence of the uplift of the Tibetan Plateau in southwestern Yunnan block southward movement, the lower crust exists low velocity layer is block movement provided favorable conditions. But the Lincang granite on the south of rigid motion plays a backwater effect, the East and west sides of block movement rate differences, and block the movement direction of the Wuliang Mountain fault zone is a small angle. Under this background, no amount of mountain fault zone is horizontal dextral strike slip, a slide decomposition of strain effect. At the intersection with transverse faults or in the fracture end, the stress concentration and easy to cause earthquakes, the MS6.6 earthquake occurred at the end of fracture. According to the field survey expedition, in the macroscopic epicentral region from banded sand liquefaction and To crack the ground damage. Blasting hole Beaded linear distribution, mainly NW and NE two groups; NW to crack a right order en echelon, NE to crack a left Jieyan miracle arrangement, they have obvious tectonic origin. The long axis direction of the earthquake intensity, the aftershock distribution and focal mechanism solutions show the earthquake, face to the NW section along the dextral strike slip caused by macro ground damage characteristics and microscopic observation results show that the earthquake rupture, consistent with Jinggu Yunxian fault movement, the seismogenic structure should be Jinggu Yunxian fault.

【作者单位】：云南省地震局;中国地震局地质研究所活动构造与火山实验室;
【基金】：国家自然基金项目(41472204)资助
【分类号】：P315.2

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