Fully recognize various problems in the observed magnetotelluric(MT)data is the precondition of inverse solutions.In the paper,according to the geomorphological conditions of the observational MT stations in the Guang...Fully recognize various problems in the observed magnetotelluric(MT)data is the precondition of inverse solutions.In the paper,according to the geomorphological conditions of the observational MT stations in the Guangxi area,we constructed several different kinds of models to conduct a three-dimensional forward simulation of the MT fi eld using the vector fi nite element method(FEM).First,the variation rule and differences of apparent resistivityρxy andρyx in the xy and yx modes were studied and analyzed,and then the geoelectric information refl ected by the change of apparent resistivityρxx andρyy were discussed.Final,the responses of typical geological structures that cause a static shift problem were presented.The synthetic examples showed thatρxy andρyx were relevant to the layout of the survey line,for instance,ρxy had different values along the west-east profi le compared with that of the southnorth profi le,Moreover,ρxx andρyy could subtly show the abnormal body-host rock interface,which could be used to restrict the anomalous domain in the inversion process.In addition to the scale and depth of the top surface of the anomalous body,the widespread rivers and hills,can simulate static shift.Hence,to reduce the infl uence of static shift on MT data,a reasonable distance between a station and rivers or hills should be considered in accordance with the scale of rivers or hills.展开更多
基金This paper was partially supported by the National Natural Science Foundation of China(No.41674075 and 41904123)the Natural Science Foundation of Guangxi Province(No.2016GXNSFGA380004)and the High Level Innovative Team and Excellent Scholar Plan of Guangxi High Education Institution.
文摘Fully recognize various problems in the observed magnetotelluric(MT)data is the precondition of inverse solutions.In the paper,according to the geomorphological conditions of the observational MT stations in the Guangxi area,we constructed several different kinds of models to conduct a three-dimensional forward simulation of the MT fi eld using the vector fi nite element method(FEM).First,the variation rule and differences of apparent resistivityρxy andρyx in the xy and yx modes were studied and analyzed,and then the geoelectric information refl ected by the change of apparent resistivityρxx andρyy were discussed.Final,the responses of typical geological structures that cause a static shift problem were presented.The synthetic examples showed thatρxy andρyx were relevant to the layout of the survey line,for instance,ρxy had different values along the west-east profi le compared with that of the southnorth profi le,Moreover,ρxx andρyy could subtly show the abnormal body-host rock interface,which could be used to restrict the anomalous domain in the inversion process.In addition to the scale and depth of the top surface of the anomalous body,the widespread rivers and hills,can simulate static shift.Hence,to reduce the infl uence of static shift on MT data,a reasonable distance between a station and rivers or hills should be considered in accordance with the scale of rivers or hills.
