The Study On 2D Inversion Of 3D Magnetotelluric Forward Data

The Current study of 3D magnetotelluric inversion algorithm are still largely focused on 1D and 2D inversion algorithm, three-dimensional magnetotelluric inversion algorithm is still a very complex problem, the aspect of calculation accuracy and computational efficiency remains to be improved. In recent years, the research of the three-dimensional magnetotelluric inversion method has made a greater development, but there is few applications in practical terms, its effect remains to be further verified in the practical application, So under existing conditions, it is necessary to explore the effect of the two-dimensional inversion method for three-dimensional magnetotelluric forward data, in the paper, we explore the effect of the two-dimensional inversion method for three-dimensional magnetotelluric forward data in different polarization mode ? the striking length of the low resistivity body?relative location of line?the angle of the line and body striking and the depth of body buried and terrain.We first analyze the two-dimensional magnetotelluric REBOCC inversion algorithm, Computing in the algorithm for the simple model, and analyzing the effect in different polarization mode, the resistivity of initial model, numbers of measured stations and frequency, the RMS for the REBOCC inversion algorithm.Then, then we calculate using three-dimensional magnetotelluric forward for the typical model, proving the reliability of the algorithm, then we analysis the two-dimensional inversion algorithm for three-dimensional magnetotelluric forward modeling, and analyzing in different polarization mode the effect of the striking length of the low resistivity body?relative location of line?the angle of the line and body striking and the depth of body buried and terrain for result in two-dimensional inversion algorithm. we find that the result of TE polarization mode of inversion can better reflect the body resistivity, but producing distortion, the result of TM polarization mode of inversion can better reflect the position of body, but it can't reveal the real value of bodyresistivity, the result of TE +TM polarization model of inversion has the advantages of both, but it also produces distortion. As the increasing of the striking length of the body length, the results of two-dimensional inversion is more reliable, as the distance increasing of line migration, the results inversion is worse, the angle of line and body striking is smaller, the effect of inversion is unreliable, as the depth of body increasing, the results inversion is worse and terrain has greater effects on the result in the two-dimensional inversion algorithm for three-dimensional magnetotelluric forward modeling.