Dual channel radar resistivity tomography and its application
Resistivity is an important physical property of rock.It is a basis to identify stratum,lithology,minerals,water content and tectonic setting for geological environment.In order to obtain the resistivity distribution in geological section accurately,a new resistivity tomography method is developed by using dual channel radar.The dual channel radar can record both of the transmit and received signals at the same time.The trave time of electromagnetic wave along the path in geological section are determined by the time difference between the transmit and received signals.The attenuation of electromagnetic wave in the path is measured reliably by amplitude ratio between the transmit and received signal.Using travel time of all paths,the velocity distribution is inverted following Radon principle.After conducting velocity tomography,the resistivity variable in the attenuation equation can be linearized by using the decoupling matrix which is constitutive with the element velocity values.Using all of amplitude ratio,the resistivity distribution of the section is finally obtained by solving the linearized attenuation equation.Compared to direct current resistivity tomography method,this technique offers better resolution,more reliable,and avoiding the difficulty to lay electrodes in the holes.In an application,quartz veins and mica enrichment zones are identified in granite with high resistivity and high velocity anomalies.Radar resistivity tomography is a new technology,which has bright future in hydrogeology,engineering and minerals exploration projects.
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