pySATSI

Python package for focal mechanism stress inversions.

Author: Robert Skoumal, U.S. Geological Survey | rskoumal@usgs.gov

This project contains Python code to compute damped stress inversions using earthquake focal mechanism solutions.

How to Use

1. Install the latest release in your virtual environment:

# If you don't want to create any plots:
pip install -U pySATSI

# If you do want to create plots:
pip install -U 'pySATSI[plot]'

Python 3.8+ versions are supported.

2. Run pySATSI with your desired control file:

pySATSI path_to/control_file.txt

More information

Running examples

A variety of examples are provided in the repository. It's recommended you play around with these examples to learn about some of the features.

1. Download the examples folder available HERE.
2. Unzip the folder.
3. Navigate to the examples folder you just downloaded, e.g.: cd examples
4. Run pySATSI with the example of your choice, e.g.: pySATSI 0D/control_file.txt

Manual

Refer to the manual or the wiki for additional information about running the code.

Citation

Please cite our paper if you use anything in this project:

• Skoumal, R.J., Hardebeck, J.L., Michael, A.J. (2026). pySATSI: A Python package for computing focal mechanism stress inversions. Seismological Research Letters. https://doi.org/10.1785/0220250182

Significant portions of this algorithm are based on SATSI:

• Hardebeck, J.L., & Michael, A.J. (2006). Damped regional‐scale stress inversions: Methodology and examples for southern California and the Coalinga aftershock sequence. Journal of Geophysical Research: Solid Earth, 111(B11). https://doi.org/10.1029/2005JB004144

License and Disclaimer

License: This project is in the public domain.

Disclaimer: This software is preliminary or provisional and is subject to revision.