敦化-密山断裂带及周边地区的航磁特征与深部构造  

THE CHARACTERISTIC AND DEEP STRUCTURE OF THE GEOMAGNETICS IN AND AROUND THE DUNHUA-MISHAN FAULT ZONE

作　　者：王禹丹 张景发 田甜 WANG Yu-dan;ZHANG Jing-fa;TIAN Tian(National Institute of Natural Disaster Hazards,Ministry of Emergency Management,Beijing 100085,China;China University of Geosciences(Wuhan),Wuhan 430074,China)

机构地区：[1]应急管理部国家自然灾害防治研究院,北京100085 [2]中国地质大学(武汉),武汉430074

出　　处：《地震地质》2022年第2期448-460,共13页Seismology and Geology

基　　金：中国地震局地壳应力研究所基本科研业务专项(ZDJ2017-29,ZDJ2018-15,ZDJ2019-21);吉林省科技发展计划项目(20180201034SF)共同资助。

摘　　要：文中利用小波多尺度分析法对敦化-密山断裂带北端及周边区域地区的航磁数据进行反演,分析了不同深度下的地壳磁性特征,对敦化-密山断裂与周边断裂的深部构造特点及交切关系进行了探究,同时利用Parker法反演了该区域磁性层的下界面,得到该区域的居里面深度。结果表明:在航磁浅源场中,浅地表及上地壳介质比较复杂,敦化-密山断裂带表现为串珠状的小尺度异常;在航磁深部场中,中上地壳主要是盆地构造基底岩石的磁性不同导致的磁异常,断裂带形成磁性梯度带,影响了航磁特征,并切穿至居里面。区域居里面的埋深为22.3~29.9km,埋藏较深的区域位于虎林县南,敦化-密山断裂带对该区域的居里面分布具有控制作用。文中同时结合发震规律与莫霍面分布,探讨了该区域地壳的稳定性。This paper focuses on the in-depth analysis of the aeromagnetic characteristics of the Dunhua-Mishan fault zone and its surrounding areas using wavelet multi-scale analysis.In order to analyze the anomalies of the crustal structure at different depths,wavelet multi-scale decomposition is used to separate the deep field from the shallow field sources,superimpose the aeromagnetic anomalies on different anomalies of different geological bodies,extract the required information,analyze the local field anomalies caused by the field sources,and invert and interpret the geological bodies.In this paper,wavelet multi-scale analysis is used to decompose the aeromagnetic data,separate the deep and shallow field sources of aeromagnetism in the study area,and obtain wavelet detail maps of order 1 to 4.The wavelet transform detail maps are a response to high frequency anomaly information,and also a reflection of local field aeromagnetic anomaly information,which can be used to infer information such as fault depth and basement depth of basin.The experimental results are used to analyze the anomaly characteristics at different depths,invert and analyze the characteristics of the aeromagnetic anomalies and crustal structure at different depths,explore the deep basement and fault tectonic features and the intersection relationship between the Dunhua-Mishan Fault and the surrounding faults,calculate the approximate field source depth by wavelet detail map and power spectrum method,and infer the fault cut-through depth.The results of the analysis can provide geophysical research information for the study of geotectonics and the evaluation and exploration of hydrocarbon resources.Based on the original aeromagnetic anomaly map,aeromagnetic anomalies ranging from-494~2022 nT can be obtained,with the highest anomaly located at about 50 km from Baoqing County.The anomalies in the central part of the study area are high,while those in the eastern and western parts are low.The deposition of basal and ultramafic magmatic rocks in the Dunhua

关 键 词：敦化-密山断裂带 航磁特征 深部构造 小波多尺度分析 居里面反演 

分 类 号：P315.2[天文地球—地震学]