3.7 KiB
FEMTIC
FEMTIC is a 3-D magnetotelluric inversion code based on the following studies. FEMTIC was made using object-oriented programming with C++.
Y. Usui, 3-D inversion of magnetotelluric data using unstructured tetrahedral elements: applicability to data affected by topography, Geophys. J. Int., 202 (2): 828-849, https://doi.org/10.1093/gji/ggv186, 2015.
Y. Usui, Y. Ogawa, K. Aizawa, W. Kanda, T. Hashimoto, T. Koyama, Y. Yamaya and T. Kagiyama, Three-dimensional resistivity structure of Asama Volcano revealed by data-space magnetotelluric inversion using unstructured tetrahedral elements, Geophys. J. Int., 208 (3): 1359-1372, https://doi.org/10.1093/gji/ggw459, 2017.
Y. Usui, T. Kasaya, Y. Ogawa and H. Iwamoto, Marine magnetotelluric inversion with an unstructured tetrahedral mesh, Geophys. J. Int., 214(2): 952-974, https://doi.org/10.1093/gji/ggy171, 2018.
The website of FEMTIC: https://sites.google.com/view/yoshiyausui/femtic
Functional overview
FEMTIC gives a three-dimensional electrical resistivity structure from the response functions at observation points on the Earth's surface.
Mesh type: tetrahedral mesh, hexahedral brick mesh, and non-conforming deformed hexahedral mesh
Data type: impedance tensor, vertical magnetic transfer function, inter-station horizontal magnetic transfer function, phase tensor, apparent resistivity, and phase.
Parallel computation: Hybrid MPI/OpenMP parallel calculation can be used.
Model parameter: Subsurface electrical resistivity and distortion matrix of galvanic distortion.
Release note
v4.1 Nov. 9, 2021 This new version supports difference filter. The error calculation of log10(apparent resistivity) is modified. Rotation angles of distortion matrix are limited to from -90 to 90 (deg.) when gains and rotations of galvanic distortion are estimated.
v4.0 Jun. 3, 2021 This new version supports non-conforming deformed hexahedral mesh.
v3.5 Jan. 11, 2021 This new version supports observed data of apparent resistivity and phase and unsymmetric roughening matrix.
v3.4.7 Sep. 4, 2020 The integer indices into the multiple right-hand-side vectors and solution vectors were changed from 32-bit to 64-bit.
v3.4.6 Sep. 2, 2020 This version allows us to make resistivity of every individual subsurface element to be a different model parameter, in analogy with other 3-D inversion code.
Pre/post-processing tools for FEMTIC
Some pre/post-processing tools for FEMTIC, including meshing tools, and their manuals can be downloaded from GitHub. Results of FEMTIC can be visualized by ParaView.
makeTetraMesh: By using this tool, you can make a surface mesh for creating a tetrahedral mesh.
makeMtr: This tool output .mtr file of TetGen by reading node and .ele files of TetGen.
TetGen2Femtic: This program converts output files of TetGen to FEMTIC.
makeDHexaMesh: Tool for making non-conforming deformed hexahedral mesh for FEMTIC
makeHexaMesh: Tool for making hexahedral brick mesh for FEMTIC
mergeResultOfFEMTIC: By this program, you can merge result files (.csv) of FEMTIC.
makeCutawayForGMT: By using this program, you can make a file needed to draw a cross-section of a resistivity structure by GMT.
changeResistivityForFemtic: By this program, you can change resistivity values of a specified area for sensitivity tests of FEMTIC inversion results