TRACMT (Robust TRansfer Function Analysis Code for MagnetoTellurics)
TRACMT (Robust TRansfer Function Analysis Code for MagnetoTellurics)
Robust transfer function analysis code for magnetotellurics. In TRACMT, you can use the RRMS estimator developed by Usui et al. (2024) and the fast and robust bootstrap method evaluated by Usui et al (2025).
Yoshiya Usui, Makoto Uyeshima, Shin'ya Sakanaka, Tasuku Hashimoto, Masahiro Ichiki, Toshiki Kaida, Yusuke Yamaya, Yasuo Ogawa, Masataka Masuda, Takahiro Akiyama, 2024. New robust remote reference estimator using robust multivariate linear regression, Geophysical Journal International, ggae199, https://doi.org/10.1093/gji/ggae19_9
Yoshiya Usui, 2024. Prewhitening of magnetotelluric data using a robust filter and robust PARCOR. Bull. Earthq. Res. Inst. Univ. Tokyo, 99, https://doi.org/10.15083/0002012817
Yoshiya Usui, Makoto Uyeshima, Shin'ya Sakanaka, Tasuku Hashimoto, Masahiro Ichiki, Toshiki Kaida, Yusuke Yamaya, Yasuo Ogawa, Masataka Masuda, Takahiro Akiyama, 2025, Application of the fast and robust bootstrap method to the uncertainty analysis of the magnetotelluric transfer function, Geophysical Journal International, ggaf162, https://doi.org/10.1093/gji/ggaf162
We developed the RRMS estimator by applying the robust multivariate linear regression S-estimator to the two-input-multiple-output relationship between the local EM field and the reference magnetic field that leads to the same equation as by the original remote reference method. The RRMS estimator can give an unbiased estimate of the MT transfer function and suppress the influence of outliers in the local electric field and magnetic field.
Input file format: Text (Ascii) file / .ats files of Metronix instruments / MTH5 files (Peacock et al., 2022) / .dat files of ELOG-MT
Prewhitening: Non-robust prewhitening / Robust prewhitening / Robust prewhitening with robust filter
Transfer function estimation method: Ordinary least square / Non-robust remote reference / Robust remote reference / RRMS estimator
Error estimation method: Parametric approach / Bootstrap method / Jackknife method
Source codes, manuals, and sample input files of TRACMT can be downloaded from the following GitHub repository.
v1.2.0 Jun. 13, 2024: Initial release.
v1.3.4 July. 14, 2024: A parametric error estimation method was added for the RRMS estimator. Some bugs relating to the ELOG reading option and calibration were fixed.
v1.3.6 August. 15, 2024: A function to read ELOG-DUAL binary files was modified.
v2.0.0 January. 1, 2025: The fast and robust bootstrap method was added. Some equations of the parametric error estimation method were modified.
v2.1.0 January. 14, 2025: The equation of the AIC is modified.
v2.2.0 February. 10, 2025: The option for reading MTH5 files is added.