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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。
The Pianshan MS6.5 earthquake occurred on the Pishan reverse fault-fold belt in front of the West Kunlun Mountain. The deformation features of the structural belt are mainly fold and bend in the strata. A series of normal faults developed at the top of the anticline are the top of the anticline Local tensile stress moment stress fracture. According to the information of the emergency test of Pishan earthquake, the spatial distribution of aftershocks, the focal mechanism solution and the deep petroleum profile, the Pishan MS6.5 earthquake is a one-time thrusting event. The earthquakes did not produce any obvious earthquake fault on the earth’s surface, but a number of ground fissures were formed on the top of the anticline, which coincided with the strike of the anticlines. These fractures resulted in the uplift and uplifting of the anticlines by the earthquakes, The tectonic fractures are the direct reflection of anticline activity. This earthquake belongs to a typical fold earthquake. The tectonic deformation in front of the West Kunlun Mountains is dominated by shortening and thickening of the upper crust strata. The model of earthquake geogenesis belongs to the typical thin-skin nappe structure. The earthquake occurred on the Pishan anticline at the front of the nappe and the root of the nappe Fracture has not ruptured, its future earthquake risk deserves further attention and research.