Efficient 3D MT Inversion Using Finite-difference Time-domain Modelling

We show how a finite-difference time-domain modelling algorithm can be utilised for efficient 3D inversion of marine magnetotelluric (MT) data, and demonstrate the capability of our inversion on a synthetic salt dome. In comparison to frequency-domain modelling methods which are typically applied, two advantages of the finite-difference time-domain modelling method are (1) that it is an explicit, low-memory method; and (2) that it allows forward and adjoint computation for the electromagnetic field unknowns at all frequencies of interest in a single modelling run.