The ISC-GEM Global Instrumental Earthquake Catalogue 2017

(Updated January 2017) Version 4.0 of the ISC-GEM Catalogue is the result of the 3rd year of the Extension Project that began in November 2014. We included earthquakes smaller than 6.25 during 1920-1934 listed in the ISS but not processed in the past. We also included earthquakes that occurred in 2013. The recent data were available from the ISC Bulletin in an electronic format, but the arrival time data for earthquakes during 1920-1934 had to be digitized from the ISS and amplitude-period data added from original station bulletins in order to re-assess the magnitudes (mostly MS). The procedures used to digitize the parametric data is described in Di Giacomo et al. (2015).

Version 4.0 includes 484 earthquakes that occurred in 2013. For what concerns the period 1920-1934, we have relocated 3015 earthquakes and obtained new MS values for 2287 of them (available in the Main catalogue). The events for which we could not re-compute the magnitude are listed in the Supplementary Catalogue

As previously mentioned, we collected stations bulletins from various sources that complemented significantly the original ISC inventory of station bulletins. On top of the extension work, therefore, we decided to add amplitude data from the newly available stations bulletins also for the earthquakes that were already available in the ISC-GEM catalogue in order to improve our re‑computed MS and, as a result, the Mw proxy. With the data newly available, we better constrained the MS for 685 earthquakes between 1920 and 1934 listed in previous versions by using more station magnitudes (e.g., 67% of the original MS was obtained from NSTA <= 10, for the updated MS this percentage drops to ~20%). Finally, we revised the hypocentre locations and/or magnitude of 16 earthquakes outside the period 1920-1934.

Reference: Storchak, D.A., D. Di Giacomo, I. Bondár, E. R. Engdahl, J. Harris, W.H.K. Lee, A. Villaseñor and P. Bormann, 2013. Public Release of the ISC-GEM Global Instrumental Earthquake Catalogue (1900-2009). Seism. Res. Lett., 84, 5, 810-815,

The Catalogue is protected by the Copyright (C) 2016 GEM Foundation and the International Seismological Centre.

You may use this work under the terms of the CC-BY-SA 3.0 (unported) http://creativecommons.org/licenses/by-sa/3.0/