Catalogue Overview, Version 8.0, 06 April 2021

On the 6th of April 2021, the version 8.0 of the ISC-GEM Catalogue was publicly released. The release marked the end of the third year of the Advancement Project .

During this year we added to the catalogue a) about 2,500 earthquakes during 1991-1999 and 2017. About 1000 of those earthquakes are continental events with magnitude ≤ 5.5; b) 448 source mechanisms (in form of moment tensors and/or fault planes) from the literature for earthquakes between 1906 and 2013. The list of publications used to retrieve direct seismic moments and source mechanisms is available at

We also reprocessed 900 earthquakes between 1920 and 1945 after adding readings (mostly surface wave amplitude and period measurements) from individual station bulletins that were donated to the ISC from the University of Stuttgart (we are grateful to Rudolf Widmer-Schnidrig of the Black Forest Observatory for making this possible). Additional changes to the catalogue are listed in the update log.

Fig. 1 shows the ISC-GEM locations with symbols according to Agnew (2014) as obtained from the procedure described in Bondár et al. (2015). One feature that makes the ISC-GEM Catalogue a unique product is that the locations are achieved by the same location technique and velocity model (ak135) and comes with uncertainties for each focal parameter.

Fig.1: map showing the earthquakes listed in the Version 8.0 of the ISC-GEM Catalogue (about 42,000 earthquakes, see also Fig.2). The symbols are plotted according to Agnew (2014) and colour coded according to the ISC-GEM depth.

Fig. 2 shows the current time-magnitude distribution of the ISC-GEM Catalogue (1904-2017).

Fig. 2: Top: cumulative annual number of earthquakes with Mw ≥ 5.0 (black), Mw ≥ 5.5 (red), ≥ 6.5 (blue) and ≥ 7.5 (yellow); Bottom: time-magnitude distribution color-coded in cells of 0.1 units of Mw for each year of the ISC-GEM main catalogue. The earthquakes processed in 2017 exhibit the same distribution we can observe in recent years and add significant earthquakes to the catalogue. The biggest difference with previous versions occurs during 1991-1999, where, in the past versions, nearly no earthquake below Mw 5.5 was included. For comparison with the original version see Fig. 20 in Di Giacomo et al. (2015b), or Figure 25 in Di Giacomo et al. (2018) for the comparison with Version 5.0.