长宁及周缘重力数据融合及深浅构造特征研究
投稿时间:2023-10-11  修订日期:2023-12-17  点此下载全文
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作者单位邮编
麻继文 防灾科技学院 430000
吴桂桔* 中国地震局地震研究所(地震大地测量重点实验室) 
邹正波 中国地震局地震研究所(地震大地测量重点实验室) 
谈洪波 中国地震局地震研究所(地震大地测量重点实验室) 
王嘉沛 中国地震局地震研究所(地震大地测量重点实验室) 
基金项目:国家自然基金青年基金(42204089),国家自然科学基金面上项目(42074172),地震星火计划攻关项目(XH21021)
中文摘要:高精度地球物理数据是获取地壳内部物质变化的基础,2019年6月17日四川长宁发生MS6.0级地震,近期该区域多次发生5级左右地震,且区域内地震的发震诱因存在争议。本研究以实测重力剖面数据为基准,首先寻找重力场模型数据与实测重力剖面数据之间的映射关系式;然后对重力场模型数据进行修正,采用双线性插值法获取研究区内高精度网格数据;以长宁MS6.0地震震中为中心点,提取4条重力剖面并采用密度反演获取跨长宁MS6.0地震震中的地壳密度变化特征。研究结果表明:通过重力场模型数据与实测重力数据间的映射关系式计算所获取的融合数据精度小于5%;长宁及周边震群发震区域对应三叠系地层且震群多沿背斜、向斜发生;长宁MS6.0地震位于剩余布格重力异常0mGal-30mGal的正低值区域和密度反演高低转换带上0.048 g/cm3-0.058 g/cm3的正低值区域,该区域处于长宁背斜上的大地湾断层与双河背斜轴部隐伏断层的交汇处。本研究可为多源重力数据融合提供技术基础,服务于以动力学为基础的地震物理预测。
中文关键词:重力数据融合  布格重力异常  长宁地震  视密度成像
 
Research on gravity data fusion and deep-shallow structure characteristics in Changning and its periphery
Abstract:High-precision geophysical data is the basis for obtaining material changes inside the crust. On June 17, 2019, a MS6.0 earthquake occurred in Changning, Sichuan Province. Recently, there have been several earthquakes of about 5 magnitude in this region, and the causes of earthquake occurrence in this region are controversial. Based on the measured gravity profile data, the mapping relationship between the gravity field model data and the measured gravity profile data is first sought. Then, the gravity field model data is modified, and the high-precision grid data in the study area is obtained by bilinear interpolation. Taking the epicenter of the Changning MS6.0 earthquake as the central point, four gravity profiles were extracted and the characteristics of crustal density variation across the Changning earthquake epicenter were obtained by using the density inversion method. The results show that the accuracy of the fusion data obtained by the mapping relationship calculation between the gravity field model data and the measured gravity data is less than 5%. The earthquake clusters in Changning and its surrounding areas correspond to the Triassic strata and most of them occur along the anticline and syncline. The Changning earthquake is located in the positive and low value area of 0mGal-30mGal residual Bouguer gravity anomaly and 0.048 g/cm3-0.058g/cm3 density high-low transition region, and this area is the intersection of Dadiwan fault on Changning anticline and hidden fault on Shuanghe anticline axis. This study can provide the technical basis for multi-source gravity data fusion, and serve the dynamic based seismic physical prediction.
keywords:Changning earthquake  Gravity data fusion  Bouguer gravity anomaly  Density inversion
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