基于GNSS／InSAR／GIS的活动断层地震危险性评估系统

摘要

The method to evaluate seismic hazards of active faults according to the Coulomb failure criteria using theGNSS, tnSAR, gravity, leveling and other kinds of geodetic observations is illustrated in this paper. The design for the corresponding evaluating system was presented. The system uses these geodetic data to determine the crustal deformation near active faults and implement the inversion for the strain, stress and motion parameters of active faults. Then the threshold values of stress of active faults are fixed from geological and seismic data and analyze the sites, maximum magnitudes, recurrence time and probability of potential earthquakes using the evaluating models. The system exhibits, interprets, and manages the evaluating results using GIS. As a demonstration, the coseismic Coulomb stress triggered by 2008 Wenchuan earthquake, the lasting time of stress disturbing and the earthquake rate of Lonqmenshan area after shock are discussed.%从GNSS、lnSAR、重力、水准等多种大地测量资料联合确定活动断层地壳形变、应变和应力，以及与GIS相结合的角度出发，讨论基于库仑破裂准则的活动断层地震危险性评估方法，系统阐述活动断层地震危险性评估系统的设计。该系统主要利用各种大地测量数据联合确定活动断层区域的位移场，反演计算应变场、应力场、活动断层运动参数以及库仑应力；通过确定活动断层的临界应力值，建立地震危险性评估模型，评估可能发生地震的位置、最大震级、复发时间及其对应的概率；最后借助GIS实现断层区域的地质和构造环境、三维形变数据、应变场、应力场和地震危险性综合评价图的管理与可视化。最后针对所建系统的具体应用，讨论汶川地震激发的同震静态库仑应力、应力扰动的持续时间和龙门山地区的地震活动率。