Easily plot focal mechanisms (beachballs) onto a map. Uses the ObsPy library under the hood, to render beachball plots as SVG icons.



Workflow is split into 2 steps:

1. Beachball plots are created from a layer of events, and rendered as SVG icons. The icons are saved (by default in a folder called 'beachball_svgs' in the project directory) and named based on the selected ID field (may be an fid or an event name/identifier, but it must be unique).

2. A layer symbology is created, using SVG markers with a data-defined expression, to load the SVG for each event based on the selected id field/event name.

The user can then easily modify the symbology (e.g. change the marker size).


Required fields:The data at hand, must contain the 6 moment tensor components (Mrr, Mtt, Mpp, Mrt, Mrp, Mtp) and the event location (latitude, longitude, depth).


Warning: creating the SVGs is currently done in the main thread, so for large datasets, the process may take a while, during which QGIS may appear unresponsive. This will be delegated to a processing provider in the next version.


Input format:You can use a CSV/TSV file tutorial or any other vector layer (e.g. shapefile, geopackage) with the required fields. You can find a sample dataset, extracted from the GCMT Catalog, here

Python dependencies: The plugin requires the obspy, matplotlib, numpy packages. Upon installing the plugin, you will be prompted to install them. In some cases, this may fail you need to install it manually. In this case, search for manual python dependency installation in QGIS, or email me to try and troubleshoot it together.
The plugin was bootstraped using this amazing article by Richard Styron.


Citation: If you use this plugin in your research, please cite it as:

Efstathios Lymperis (2025). QBeachball: A QGIS plugin for plotting focal mechanisms, based on the ObsPy library. Version 1.0.0 URL: https://github.com/lymperis-e/qbeachball [last accessed yyyy/mm/dd]


You may also like to cite ObsPy, the library used under the hood.