Moment Tensor Homepage
The Berkeley Seismological Laboratory (BSL) routinely determines moment tensors for events occurring in Central and Northern California, and for notable earthquakes in the western US. Most of the mechanisms, particularly for California events, have been migrated from the old flat file catalog to the database of the Northern California Seismic System.
In the past, the BSL operated two automated moment tensor algorithms. Currently, only the three-component complete waveform inversion is used to attempt a preliminary (automatic) moment tensor solution within 6-9 minutes of an earthquake. Excellent solutions (variance reduction > 80%) are posted automatically to the web. All events with M>3.5, are reviewed by an analyst. If a solution is deemed acceptable, it is submitted to the database, disseminated via email and is posted to the web.
- NCEDC Moment Tensor Catalog Search. As "Input Catalog", choose the Mechanism Catalog. Output formats for moment tensors are: psmeca (for plotting with GMT), the format of the old BSL Moment Tensor Catalog (see below), and a format like that of the Global CMT simple reports.
- NCEDC Moment Tensor Archive(View solutions of individual events)
- Old Moment Tensor Catalog (flat file) and format description. (no longer updated)
- Annual Moment Tensor Maps (last updated July 1, 2016)
- BSL Moment Tensor References
- Earthquakes of Special Interest