Research on the Effect of 3D Body Between Transmitter and Receivers on CSAMT Response Using Integral Equation Method

Abstract

AbstractIn the field work using the Control Source Audio‐frequency Magnetotelluric method, the space between the transmitter and the receivers is up to several kilometers. In order to study the effect of the anomalous body locating at between the transmitter and the receivers, we simulate the CSAMT response using 3D Contraction Integral Equation method. First we simulate the response of the target body in the survey area. We found that the center of the anomaly locates above the target at high frequency but shifts slowly away from the source with the frequency decreasing, therefore 3D interpretaion method should be considered if there is a 3D anomalous target body in the survey area. Then we simulate the effect of 3D anomalous body between the transmitter and receivers on the response of the target body in the exploration area. The 3D anomalous body could affect the response of the target only when the size of the anomalous body is large enough, otherwise the effect can be ignored. The effect is large when the anomalous body extends in source direction; it is medium when the body extends in horizontal direction and low when extending in vertical direction.