CSAMT法在莆田市断裂活动性调查与区域地壳稳定性评价中的应用  

Application of CSAMT Method in the Investigation of Fault Activity and Evaluation of Regional Crustal Stability in Putian

作　　者：陈志伟[1] Chen Zhiwei(Fujian Province 121 Geological Brigade,Fujian Coalfield Geology Bureau,Longyan Fujian 364021,China)

机构地区：[1]福建省煤田地质局福建省121地质大队,福建龙岩364021

出　　处：《工程地球物理学报》2023年第1期24-31,共8页Chinese Journal of Engineering Geophysics

基　　金：中国地质调查局科研项目(编号:水[2014]02-012-010)。

摘　　要：为查明福建省莆田地区重点建设区断裂活动性与区域稳定性,进而指导城市的规划、设计和工程建设,莆田市以城市地质调查为契机,开展了主要断裂活动性调查与区域地壳稳定性评价专题工作。采用可控源音频大地电磁法(Controlled Source Audio Frequency Magnetotelluric Method,CSAMT)为主,高密度电法及电阻率测深为辅的地球物理勘查方法,通过对莆田重点建设区内沙县—南日岛、东郊—涵江及陂头—西天尾三条断裂的CSAMT探测成果对比分析。查明了探测区域内地层厚度规律和构造的规模形态、充填情况等信息,总结了莆田断裂构造的电性特征和展布规律并与钻探验证资料吻合。结果显示,CSAMT能有效分辨埋深1 km以内断裂构造的纵向及横向电性差异情况,以电阻率等值线图推测的地质信息为基础,结合区域地震、地温差异等因素能对断裂的活动性、稳定性进行综合评价和定性分析研究。其探测成果为城市的空间利用、工程规划和地质灾害防治等工作提供了科学依据。In order to find out the fault activity and regional stability in the key construction area of Putian city,Fujian province,and to guide the planning,design and engineering construction of the city,Putian city has taken the urban geological survey as an opportunity to carry out the investigation of the main fault activity and regional crustal stability evaluation of the special work.Based on the geophysical exploration methods of controlled source audio-frequency magnetotelluric(CSAMT),high density electrical method and resistivity sounding,the paper compared and analyzed the CSAMT detection results of Shaxian-Nanridao,Dongjiao-Hanjiang and Pitou-Xitianwei faults in Putian key construction area.The patterns of the interior layer,the scale and shape of the structure and the filling situation of the exploration area are found out,and the electrical characteristics and distribution patterns of the Putian fault structure are summarized,which are consistent with the drilling verification data.The results show that CSAMT can effectively distinguish the longitudinal and transverse electrical differences of faults within 1 km buried depth.Based on the geological information inferred from the resistivity contour map,combining with regional earthquake and geothermal differences,the activity and stability of faults can be comprehensively evaluated and qualitatively analyzed.The exploration results provide scientific basis for urban space utilization,engineering planning and geological disaster prevention and control.

关 键 词：CSAMT 断裂活动性 地壳稳定性 地质灾害 

分 类 号：P631.325[天文地球—地质矿产勘探] P622[天文地球—地质学]