龙门山和相邻地域航磁场特征与汶川大地震  

Aeromagnetic field characteristics and the Wenchuan earthquakes in the Longmenshan mountains and adjacent areas

作　　者：闫亚芬[1] 滕吉文[1] 阮小敏 胡国泽[3] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]斯伦贝谢(中国)地球物理中心,北京100015 [3]东北大学秦皇岛分校,河北秦皇岛066004

出　　处：《地球物理学报》2016年第1期197-214,共18页Chinese Journal of Geophysics

基　　金：国家科技支撑计划"汶川地震断裂带科学钻探"(13);973项目"汶川地震发生机理及其大区动力环境研究(1-3)"(2008CB425701)联合资助

摘　　要：本文应用化极、水平及垂向导数、向上延拓、视磁化强度填图及磁性界面反演等方法处理了龙门山及相邻地域最新的航空磁测数据,分析了龙门山及相邻地域的航磁异常展布特征.研究结果表明:1)龙门山造山带与其东、西两侧可划分为三个磁异常区:松潘—甘孜磁异常区、龙门山负磁异常带、四川盆地磁异常区;三个区、带的地壳介质磁性结构存在明显差异.2)根据该区航空磁异常场的分布特征分别研究了,松潘—甘孜地块、龙门山造山带和四川地块的磁场特征.3)除识别前人识别的断层外,还推断鲜水河ES延伸甘洛—雷波北断裂作为四川盆地与滇西的界带.4)航空磁异常,磁性体上、下界面及磁源体深度的空间分布特征与汶川MS8.0大地震及芦山地震发生相关.In this paper,we analyzed the aeromagnetic anomaly data in the Longmenshan mountains and adjacent areas by different methods,such as vertical magnetization,horizontal and vertical derivation,upward continuation,frequency and wavelet transform.The results show that the characteristics of magnetic anomalies suggest this area could be divided into three magnetic anomaly blocks which have different medium properties in crust.They are the SongpanGarzêmagnetic anomaly area,the Longmenshan negative area,and the magnetic anomaly area in the Sichuan basin. The analysis of aeromagnetic anomaly characteristics reveals spatial distribution of the tectonic units and major faults in the Longmenshan mountains,Sichuan basin and the plateau in western Sichuan.There is a correlation between the aeromagnetic anomalies,top and bottom depths of the magnetic bodies and the 2008 Wenchuan MS8.0earthquake.

关 键 词：龙门山造山带 航空磁异常场 介质属性 区域构造 汶川地震 

分 类 号：P315[天文地球—地震学]