2.5 D controlled source audio-frequency magnetotellurics OCCAM inversion

Occam inversion is a regularization inversion to generate smooth models.The smoothest model is sought to the criterion that minimizes the misfit to the data.As resistivity of underground medium changes continually, Occam inversion considers both lateral and vertical roughness of underground medium.It avoids resistivity of model be interrupted arbitrarily.The paper takes a layered model and with two abnormities models for example,uses finite element methods of 2.5 dimensional controlled source audio-frequency magnetotellurics to calculate response,then finds the models that fitting the response data by Occam inversion method.The results show that Occam inversion to CSAMT data is stable and convergent,the app-resistivity lines with high coherence,the misfit of a set data less than 3%,and the smoothness is presented in inversion results.