Catalogue Overview, Version 10, 21 March 2023

On the 21st of March 2023, the version 10 of the ISC-GEM Catalogue was publicly released. The release marked the end of the first year of the ISC-GEM Improvement Project .

During this year we added to the catalogue: a) 18,576 earthquakes that occurred between 1976 and 2018 and with direct Mw from GCMT between 5.0 and 5.5 (hence complementing the continental earthquakes down to magnitude 5 added in previous versions); b) 1663 earthquakes that occurred in 2019 with Mw down to 5.0 globally. Finally, we have updated the Mw for three earthquakes using recent results from the literature. The list of publications used to retrieve direct seismic moments and source mechanisms is available at http://www.isc.ac.uk/iscgem/mw_bibliography.php.

Details about 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 10 of the ISC-GEM Catalogue (about 69,000 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 (1904-2019).



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. 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.