九寨沟7.0级地震的地震断裂及震源破裂的构造动力学机理研究

发布时间：2019-07-10 20:25

【摘要】：本文针对九寨沟7.0级地震的发震构造及震源破裂的构造动力学问题,从地质调查、测试与震源构造动力学理论分析相结合的角度阐明:此次地震发生在处于高法向应力左旋剪切受力状态的岷山隆起带北端与西秦岭地槽褶皱带之南缘文县—玛沁断裂相交汇部位;沿"九寨天堂"—震中—五花海以及上四寨村—中查—比芒一线发育的两条具有构造破裂特征的NW向地裂缝带,是"隐伏状"地震断裂错动造成的地表同震破裂,前者是本次地震的控震构造,后者是NW向断层的次级同震复活及扩展;此次地震的震源断层错动过程受NW331°走向的陡倾角(∠87°)断层节面控制的走滑型剪切破裂,断裂两端的剪切破裂表现出持续扩展趋势;震源构造动力学过程实质上是地壳深部沿NW方向左旋剪断"凸出体";地震断裂带两端破裂扩展的持续发展,将导致地壳"凸出体"逐步剪断贯通。
[Abstract]:In view of the tectonic dynamics of the occurrence structure and source rupture of Jiuzhaigou M _ S7.0 earthquake, it is clarified from the point of view of geological investigation, test and theoretical analysis of focal tectonic dynamics that the earthquake occurred at the intersection of the northern end of the Minshan uplift belt in the state of high normal stress left-lateral shear stress and the Wenxian-Maqin fault in the southern margin of the West Qinling geosynclinal fold belt. The two NW trending ground fissures developed along the "Jiuzhai Paradise"-epicenter-Wuhuahai and Shangsizhaicun-Zhongcha-Bimang line are the co-seismic rupture of the surface caused by the dislocation of the "hidden" earthquake fault, the former is the earthquake-controlling structure of the earthquake, and the latter is the secondary co-shock resurrection and expansion of the NW trending fault. The dislocation process of the focal fault in this earthquake is controlled by the steep dip angle (87 掳) of the fault node plane of NW331 掳), and the shear fracture at both ends of the fault shows a trend of continuous expansion; in essence, the dynamic process of the source structure is the left-handed shear "protruding body" in the deep crust along the NW direction; the continuous development of the rupture and propagation at both ends of the seismic fault zone will lead to the gradual shear and penetration of the crustal "protruding body".
【作者单位】：地质灾害防治与地质环境保护国家重点实验室(成都理工大学);中国科学院成都山地灾害与环境研究所;中国科学院大学;
【基金】：国家自然科学基金创新研究群体科学基金(41521002) 中国科学院重点实验室开放基金“断裂带内动力作用与表生灾变效应的能量耦合研究”(KLMHESP-17-06)资助
【分类号】：P315.2

【相似文献】