川滇地区重力异常与断裂分布研究  

Gravity Anomalies and Fault Distribution in Sichuan-Yunnan Region

作　　者：范潍箐 许志河 邓淼 杨耀[3] 顾观文 万永魁 王顺吉 王英杰 FAN Weiqing;XU Zhihe;DENG Miao;YANG Yao;GU Guanwen;WAN Yongkui;WANG Shunji;WANG Yingjie(School of Earth Sciences,Institute of Disaster Prevention,Sanhe 065201,China;Langfang City Key Laboratory of Earth Exploration and Information Technology,Sanhe 065201,China;Sichuan Earthquake Agency,Chengdu 610000,China)

机构地区：[1]防灾科技学院地球科学学院,河北三河065201 [2]廊坊市地球探测与信息技术重点实验室,河北三河065201 [3]四川省地震局,四川成都610000

出　　处：《防灾科技学院学报》2024年第3期50-58,共9页Journal of Institute of Disaster Prevention

基　　金：中央高校基本科研业务费(ZY2022024);山东省深部金矿探测大数据应用开发工程实验室开放课题(SDK202221)。

摘　　要：为提高地震预警能力以及为减灾工作提供科学依据,利用卫星重力对川滇地区开展大尺度的重力异常特征、地震断层和地震机制研究。通过对卫星重力数据精细化处理,揭示川滇地区地震断裂性质和地震机制。布格重力异常研究结果显示,龙门山断裂带重力异常范围为-50~200mGal,鲜水河断裂带为-350~-500mGal,则木河断裂带为-200~50mGal,安宁河断裂带为-300~-50mGal。重力异常显示龙门山断裂向北西移动,安宁河为东西倾向,则木河为北西倾向。不同解析方法显示哈克法可明确地块边界,罗森巴赫法能更好地描绘断裂空间分布。4条断裂带的重力异常变化源于地块挤压作用形成的“Y”字型交汇,研究结果表明:(1)通过卫星重力获取的布格重力值,能较好地反映该区不同块体的重力异常特征;(2)川滇地区四阶趋势分析求取的剩余重力异常,可较好地反映该区地质体异常形态;(3)龙门山、安宁河、则木河和鲜水河断裂重力梯度异常带由松潘-甘孜地块及地壳高密度物质向东南和北东方向的挤压造成。To improve earthquake early warning capabilities and provide scientific basis guidance for disaster reduction in Sichuan-Yunnan region,the satellite gravity was used to study the large-scale gravity anomaly characteristics,seismic faults and seismic source mechanisms.In this paper,the seismic fault property and seismic source mechanism in Sichuan-Yunnan region were revealed by finely processing the satellite gravity data.The research results of Bouguer gravity anomaly show that the gravity anomaly ranges of the Longmenshan Fault Zone,the Xianshuihe Fault Zone,the Zemuhe Fault Zone,and the Anninghe Fault Zone are-￣50~200mGal,-￣350~-500mGal,-￣200~50mGal,and-￣300~-50mGal respectively.The Longmenshan Fault Zone is moving northwestward,and the trending of the Anninghe Fault Zone and Zemuhe Fault Zone is east-west and north-west respectively.The research results by different analytical methods show that the Huck method can clarify the boundary of the block,while the Rosenbach method can better describe the spatial distribution of the fault.The gravity anomaly changes of four fault zones are derived by the Y-shaped intersection formed by the compression of the blocks.As the results show:(1)The Bouguer gravity values could better reflect the gravity anomaly characteristics of different blocks in the study area;(2)The residual gravity anomaly obtained by the fourth-order trend analysis in Sichuan-Yunnan region can better reflect the abnormal morphology of the geological bodies in the study area;(3)The gravity gradient anomaly zone of the Longmenshan Fault Zone,the Anninghe Fault Zone,the Zemuhe Fault Zone and the Xianshuihe Fault Zone is caused by the compression of high-density materials of Songpan-Ganzi block and crust to the southeast and northeast directions.

关 键 词：川滇地区 龙门山断裂 卫星重力 重力异常 

分 类 号：P315.726[天文地球—地震学]