三河-平谷8.0级地震区浅层三维密度结构反演研究

为研究三河-平谷地震区浅层构造背景、地震孕育机理及地震与构造的关系，利用高精度重力异常数据，采用基于块体生长模式的重力三维反演算法对地震区浅层三维密度结构进行反演，并通过模拟试算验证基于块体生长模式反演方法的有效性和稳定性。高精度布格重力异常显示，三河-平谷8.0级地震位于大兴重力局部高、三河-马坊重力局部高与大厂重力低之间的交汇过渡低值区域。研究区浅层三维密度结构反演结果表明，1679年三河-平谷M8.0地震明显受NE向夏垫断裂控制，断裂两侧密度差异明显且向下延伸约10 km，推测发震部位深约10 km。

Inversion of Shallow Three-Dimensional Density Structure in Sanhe-Pinggu M8.0 Earthquake Area

In order to analyze the shallow tectonic background, earthquake inoculation mechanism and the relationship between the earthquake and the structure, we use high-resolution gravity anomaly data and gravity 3D inversion algorithm based on block growth mode to analyze the shallow 3D inversion density structure in the earthquake area. We verify the validity and stability of the method based on block growth mode inversion, and retrieve the high-resolution gravity Bouguer anomaly data in the study area. The results show that the Sanhe-Pinggu M8.0 earthquake is located in the low-value part of intersection transition of the local high gravity of Daxing and Sanhe-Mafang and the low gravity of Dachang. The inversion results of the shallow 3D density structure of the study area show that the Sanhe-Pinggu M8.0 earthquake is obviously controlled by the NE-trending Xiadian fault. The density difference on both sides of the fault is obvious and extended down about 10 km. It is estimated that the earthquake occurred at a depth of about 10 km.