新疆皮山M_S6.5地震——发生在西昆仑山前的一次褶皱地震

发布时间：2019-02-17 20:12

【摘要】：皮山MS6.5地震发生在西昆仑山前的皮山逆断裂-褶皱带上,该构造带的变形特征以地层的褶皱弯曲为主,在背斜顶部发育的一系列正断层是背斜顶部局部拉张应力产生的弯矩断层。根据皮山地震应急科考资料,结合精定位后的余震空间分布信息、震源机制解和深部石油剖面等资料认为,皮山MS6.5地震是1次逆冲型破裂事件。本次地震在地表没有产生明显的地震断层,但在背斜顶部形成多条与背斜走向一致的地裂缝;这些裂缝是地震致使背斜隆升褶皱,在背斜地层转折部位弯曲褶皱幅度最大的地带产生的构造裂缝,是背斜活动的直接反映;本次地震属于1次典型的褶皱地震。西昆仑山前的构造变形以上地壳地层的缩短和增厚为主,地震孕育模型属于典型的薄皮推覆构造,本次地震发生在推覆体前缘的皮山背斜上,推覆体根部断裂尚未发生破裂,其未来的地震危险性值得进一步关注和研究。
[Abstract]:The Pishan MS6.5 earthquake occurred in the Pishan reverse fault-fold belt in front of the West Kunlun Mountains. A series of normal faults developed at the top of the anticline are moment faults caused by the local tensile stress at the top of the anticline. According to the scientific data of the Pishan earthquake emergency, combined with the spatial distribution information of aftershocks, the focal mechanism solution and the deep petroleum profile, it is concluded that the Pishan MS6.5 earthquake is a thrusting rupture event. There are no obvious seismic faults on the surface of the anticline, but there are many fractures on the top of the anticline that are consistent with the anticline strike. These fractures are the direct reflection of anticline activity in the area where the fold amplitude is the largest at the turning point of the anticline. The earthquake belongs to a typical fold earthquake. The crustal strata above the tectonic deformation in the West Kunlun Mountains are mainly shortened and thickened. The seismogenic model belongs to the typical thin skin nappe structure. The earthquake occurred on the Pishan anticline in the front edge of the nappe, and the fault at the root of the nappe has not yet been ruptured. The future seismic risk deserves further attention and study.
【作者单位】：新疆维吾尔自治区地震局;
【基金】：国家自然科学基金(41672208,41102137) 地震动力学国家重点实验室开放基金(LE1413)共同资助
【分类号】：P315

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