ElectroMagnetic Simulation in Geophysics#

emsig are open-source codes to simulate electromagnetic data. Their main targets are geophysical applications (exploration and monitoring, engineering, environmental), but they are by no means limited to that. Currently there are two main codes, empymod and emg3d. The former is a 3D code for layered media, the latter is a low-memory multigrid solver for 3D media. Both are written in Python and released under the permissive Apache-2.0 license.

3D EM modeller for 1D VTI media

empymod.emsig.xyz

The modeller empymod can compute electric or magnetic responses due to a 3D electric or magnetic source in a layered-earth model with vertical transverse isotropic (VTI) resistivity, VTI electric permittivity, and VTI magnetic permeability, from very low frequencies (DC) to very high frequencies (GPR). The computation is carried out in the wavenumber-frequency domain, and various Hankel- and Fourier-transform methods are included to transform the responses into the space-frequency and space-time domains.

pip install empymod

conda install -c conda-forge empymod

Multigrid solver for 3D EM diffusion

emg3d.emsig.xyz

The modeller emg3d is a multigrid solver for 3D EM diffusion with tri-axial electrical anisotropy. The matrix-free solver can be used as main solver or as preconditioner for Krylov subspace methods, and the governing equations are discretized on a staggered Yee grid.