滇西南2014年景谷中-强震群的地质构造成因——茶房-普文断裂带贯通过程的构造响应

发布时间：2018-12-16 22:12

【摘要】：2014年10—12月期间,云南景谷接连发生了Ms6.6、Ms5.8、Ms5.9三次中-强地震。为确定地震的地质构造成因,在地表调查的基础上,综合该区的地质构造情况、烈度与余震分布、震源机制解等资料,确定此次震群活动的宏观震中位于永平盆地东南侧山地,发震断层为地质与地貌表现不显著的NW向右旋走滑断层。此次震群活动及余震迁移过程指示,由于断层斜接部位岩桥的临时阻碍,Ms6.6地震破裂在向南东扩展过程中发生短暂停滞,突破障碍后进一步引发了Ms5.8和Ms5.9地震,这符合震源破裂沿NW向发震断裂分段破裂的行为。区域活动断裂的遥感解译结果发现,发震断层位置恰好处于NW向右旋走滑的茶房断裂与普文断裂之间,区域上属于该断裂带的不连贯部位,指示此次中-强震群活动应该是茶房-普文断裂带贯通过程的构造活动表现。结合思茅地块的历史地震资料发现,思茅地块地震活动多以小于等于6.8级为主,发震构造多为NW向断裂。指示在现今构造应力场作用下,该区NW向断裂的活动性相对NE向断裂更加显著,属于该区主要控震构造,应在今后的地震地质工作中给予更多关注。
[Abstract]:During October-December 2014, three moderate-strong Ms6.6,Ms5.8,Ms5.9 earthquakes occurred in Jinggu, Yunnan Province. In order to determine the cause of the geological structure of the earthquake, on the basis of surface survey, combining the data of geological structure, intensity and aftershock distribution, focal mechanism solution and so on, it is determined that the macro epicenter of the earthquake swarm is located in the mountainous area southeast of Yongping basin. The seismogenic fault is a NW strike-slip fault with no obvious geological and geomorphologic features. The swarm activity and aftershock migration process indicate that because of the temporary obstruction of the rock bridge at the fault diagonal junction, the rupture of the Ms6.6 earthquake stopped briefly in the process of spreading to the south and east. After breaking through the barrier, the Ms5.8 and Ms5.9 earthquakes were further triggered. This accords with the segmental rupture behavior of the source rupture along the NW direction fault. The results of remote sensing interpretation of regional active faults show that the location of seismogenic faults is exactly between the NW right-lateral strike-slip teahouse fault and the Puwen fault, which belongs to the discontinuous part of the fault zone. It is suggested that the activity of moderate-strong earthquake swarm should be the structural activity of the transfixion process of the teahouse-Puwen fault zone. Based on the historical seismic data of Simao block, it is found that the main seismicity of Simao block is less than M = 6. 8, and the seismogenic structure is mostly NW trending fault. It indicates that the activity of the NW trending fault is more significant than that of the NE fault under the action of the present tectonic stress field and belongs to the main seismo-controlling structure in this area and should be paid more attention to in the future seismological work.
【作者单位】：中国地质大学(北京)地球科学与资源学院;中国地质科学院地质力学研究所;云南省地震局;首都师范大学资源环境与旅游学院;北京大学;
【基金】：中国地质调查局项目(编号:1212011120163、12120114002101) 国家自然科学基金项目(批准号:41171009) 中国地质科学院地质力学研究所基本科研业务费项目(编号:DXLXJK201410)
【分类号】：P315.2

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