Magnetotelluric static shift correction using an equivalent source technique

Abstract

SUMMARY The static shift caused by near-surface conductors poses a significant challenge in magnetotelluric (MT) inversion. We present a technique to remove the static shifts in MT data by using the equivalent source technique. This method is based on the assumption that all the data are measured on or above the surface. Since static shifts across multiple stations at the same frequency are in general uncorrelated, they can be identified and removed by constructing an equivalent source layer that reproduces only the coherent signal in the data observed at multiple stations. Here we use a synthetic three-dimensional model to demonstrate the technique and demonstrate the effectiveness of the method using field data sets in the presentation.