巴颜喀拉地块周缘断裂大震序列的触发机制

项目名称： 巴颜喀拉地块周缘断裂大震序列的触发机制

项目编号： No.51508534

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 建筑环境与结构工程学科

项目作者： 刘艳琼

作者单位： 中国地震台网中心

项目金额： 20万元

中文摘要： 巴颜喀拉地块由东昆仑断裂带、龙门山断裂带和鲜水河断裂带三条巨型活断层围限，其控制着一系列强震的发生，是我国地震活动最强烈的地区之一。该区域上近年来强震的连续发生加深了对块体周缘断裂的运动特征和地震活动性的认识，促进了对强震之间的触发机制的进一步研究。本申请基于断层的活动特征、地震地质资料、GPS观测数据及构造应力场等资料，研究断层-活动地块系统内近期发生的４次Ｍ≥７级的强震序列引起的应力、应变状态的变化，探讨强震之间的触发机制，为地震危险性评价、地震中短期预测提供理论基础和依据。研究内容包括：①收集已有的野外地质调查资料，建立主要活动断裂的三维几何模型和分段模型；②依据GPS监测数据及构造应力场资料确定模型边界输入；③结合地震、地质资料，确定模型参数，选择合适的岩土本构关系运用于断层界面；④对系统内4次大震发生前后的力学和运动状态进行数值模拟，研究先发大地震对后发大地震的应力触发作用。

中文关键词： 触发机制；断层-活动地块；强震记录；地震危险性；地震预测

英文摘要： Bayankala block bounded by three sets of faults including East Kunlun fault and Xianshuihe fault and Longmenshan fault, which controls a series of strong earthquakes, is a seismically active area in China. There were several strong earthquakes continuously occurred in the region in recent years to promote the recognition of movement characteristics of the faults and seismic activity and further research on earthquake triggering mechanism. In the application, the changes of stress and strain caused by the four strong earthquakes with M≥7 recently occurred in the system constituted with faults and active blocks are researched on and triggering mechanism of strong earthquake is discussed based on characteristics of fault activity and the data of seismic and geologic and the data of GPS observation data and tectonic stress field. The study will provide a theoretical basis and foundation for seismic risk evaluation and mid-short term earthquake prediction. The main contents include are as follows.① The three-dimensional geometric model and segmentation model of the major active faults are established based on existing geological data. ② The model boundary constraints are determined based on data of GPS and tectonic stress field. ③The parameters of the model are determined and the appropriate geotechnical constitutive law is chosen for fault interface combining geological data and historical seismic data of the faults. ④The mechanics and motion state of studied system before and after the destructive earthquakes is simulated.

英文关键词： Triggering mechanism;Faults-active blocks;Strong earthquake record;Seismic risk ;Earthquake prediction