基于时变重力数据的川滇地区场源模型反演和解释

时变重力信号能反映地球内部介质迁移引起的不均衡变化, 本文利用三维欧拉反褶积方法, 通过建立合适的场源模型获得最佳反演参数, 并采用水平梯度滤波法消除部分虚假发散解, 优化反演结果。 在此基础上, 利用川滇地区2015—2019年流动重力重复观测资料, 分析了不同时空尺度的区域重力场动态变化特征, 开展对川滇地区重力变化场源特征的定性和定量研究。 结果表明: 欧拉反褶积方法能有效反演重力场变化异常的场源三维空间分布特征, 反演结果与2018年12月16日四川兴文县M_S5.7地震, 2019年6月17日长宁县M_S6.0地震及同年7月4日珙县发生的M_S5.6地震位置相对应, 揭示了区域内的构造活动特征, 为地表时变重力数据的反演和解释提供了思路和方法, 同时也对捕捉与深部构造相关的地震前兆信息、 开展强震中长期预测的应用研究具有现实意义。

Inversion and Interpretation of Field-source Model Based on the Regional Time-variable Gravity Variations of Sichuan-Yunnan Region

Time-variable Gravity changes is a reflection of disproportion changes from inner earth media.Based on the 3-D euler deconvolution method,this study calculates the optimum inversion parameters by establishing a suitable field-source model,and the divergent solutions has been eliminated by the method of horizontal gradient filtering.On the basis of relative gravity observations of Sichuan-Yunnan region from 2015 to 2019,we have systematically analyzed the dynamic change of regional gravity field from different spatial-temporal scale.Then the qualitative and quantitative research of regional gravity changes field-source feature has been carried out.The results shows that:3-D spatial distribution characteristic of field-source can be inversed by euler deconvolution method,and the inversed results are consistent with the epicenter of Xingwen MS5.7 earthquake on Dec.16th,2018,Changning MS6.0 on Jun.17th,2019 and Gongxian MS5.6 earthquake on Jul.thd,2019.This study also reveals the tectonic activity characteristics of this region,and provides some reference to understand the changes of mediators during the process of earthquake preparation and tectonic movement.Meanwhile,it is also meaningful to medium and long term forecast of strong earthquake.