The ISC Bulletin as a comprehensive source of earthquake source mechanisms

Lentas, Konstantinos; Di Giacomo, Domenico; Harris, James; Storchak, Dmitry A.

In this article we summarize the availability of earthquake source mechanisms in the Bulletin of the International Seismological Centre (ISC). The bulletin in its current status contains ∼81 000 seismic events with only one associated mechanism solution and ∼25 000 events with at least two associated source mechanisms. The main sources of earthquake mechanisms in the ISC Bulletin are reported solutions provided by data contributors and ISC-computed focal mechanisms based on first motion polarities. Given the importance of using pre-determined fault plane solutions in different types of studies, here we briefly discuss the methodologies adopted by major data providers to the ISC and investigate the intra-event variability of the source mechanisms. We conclude that the overall agreement among different earthquake mechanisms for the same event as reported by different sources can show a similarity coefficient as high as 80 %, based on the rotation angles of their best-fitting double couple solutions, for the majority of the cases. The earthquake source mechanisms discussed in this work are freely available within the ISC Bulletin websearch at



Lentas, Konstantinos / Di Giacomo, Domenico / Harris, James / et al: The ISC Bulletin as a comprehensive source of earthquake source mechanisms. 2019. Copernicus Publications.


Rechteinhaber: Konstantinos Lentas et al.

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