A study on parallel computation for 3D magnetotelluric modeling using the staggered-grid finite difference method

Computation time and memory requirements are two common problems for magnetotelluric modeling of three-dimensional conductivity structures. We develop a new parallel processing scheme that can efficiently improve the computational speed of 3D magnetotelluric modeling. The scheme of 3D megnetotelluric modeling based on the staggered-grid finite difference method is implemented in frequency domain, and the calculation process of the EM field for each frequency is independent. Therefore, considering the naturally parallelizable character, the whole computation burden of all frequencies can be divided into many minor calculation tasks for single or multiple frequencies, which will be assigned to different computing nodes and parallelly calculated. In this paper, by adopting master-slave parallel mode and parallel computation with frequencies scheme, we have implemented the parallel computation of 3D MT modeling using MPI on TC5000A high-performance parallel platform. Furthermore, we tested our parallel algorithm of 3D MT modeling using two 3D theoretical models and analyzed the calculation efficiency on a multiple-nodes computer, and the results show that the parallel algorithm is effective and efficient, which lays a solid foundation for subsequent three-dimensional parallel magnetotelluric inversion.