We are happy to announce the release of hybridMT 2.0.0, our software package for seismic moment tensor inversion and refinement, together with the new version 4.4.1 of the command line application focimt. This is the largest update of the package since its publication in 2016.
hybridMT now speaks Python
Until now, the moment tensor inversion with focimt could be used from the command line and from MATLAB. From version 2.0.0, the package also contains the Python package hybridmt. It provides the moment tensor inversion (focimt) and the Hybrid Moment Tensor refinement of event clusters (hybridmt) with the same options, the same result fields and the same numbers as the MATLAB functions, so results can be exchanged between the two environments. MATLAB is not needed to use it. A first inversion takes two lines:
from hybridmt import focimt
result = focimt('examples/example2_raw.txt', jacknife=True, beach_ball_format='PNG')
and the same in MATLAB:
Solution = focimt('examples/example2_raw.txt', 'Jacknife', 'on', 'BeachBallFormat', 'PNG');
The Python package requires Python 3.10 or newer with numpy and matplotlib, and includes the Hudson source type plot and the figures of the hybridMT refinement.
What else is new
- focimt 4.4.1: corrected shading of the T and P axes of the beach balls and corrected colour options.
- More robust MATLAB functions: clear error messages for invalid input data, such as repeated event IDs or stations, and new options to control the input data statistics of the Hybrid Moment Tensor refinement.
- New documentation: the MATLAB help was updated throughout. Each MATLAB example is followed by its Python equivalent, and new chapters describe the Python package and how the MATLAB and Python results correspond. The documentation is also available as a new PDF manual.
- Demo scripts for MATLAB and Python that show the main features on the sample data in one run: inversion, uncertainty assessment, processing of a catalog and three applications of the Hybrid Moment Tensor refinement.
The Hybrid Moment Tensor refinement uses the events of a cluster to detect stations with a persistent amplitude bias, such as site effects or wrong gains, and to correct them. In the synthetic example of the package, three stations were biased by factors of 0.2, 2 and 1/3. The refinement recovers correction factors of 4.74, 0.54 and 2.72 (compared with 5, 0.5 and 3) and reduces the median RMS error of the moment tensors from 0.23 to 0.02.
Download
The new version can be requested on the hybridMT page. The package contains the MATLAB toolbox, the Python package, the focimt binary for Windows with its source code for Linux and macOS, sample data and the documentation. More information on the command line application is given on the focimt page.
When you use hybridMT in your work, please cite:
Kwiatek, G., Martínez-Garzón, P. and M. Bohnhoff (2016). HybridMT: A MATLAB/Shell Environment Package for Seismic Moment Tensor Inversion and Refinement. Seismological Research Letters 87 (4), DOI: 10.1785/0220150251.
We thank all users for their feedback. Questions and bug reports are welcome.