The fast magnetotelluric inversion of 2-D block structure

A new fast magnatotelluric 2-D inversion method has been developed, which utilizing the same method as that of rapid relax inversion (RRI) to calculate the partial derivatives of apparent resistivity with respect to model parameter and presented the model structure of Catherine de Groot-Hed-lin and Steven Constable.An approximate 2-D Jacobian is got through transforming the RRI partial derivatives to 2-D partial derivatives and ignoring the byway derivatives.Each of inversion iteration needs forward only one.The method is extremely fast comparing with the inversion method using reciprocity. Finally some synthetic models are calculated to test the method.