Catalogue Overview, Version 9.1, 27 June 2022

Updated evid 906454 (origin time = 1932-11-13 04:46:59) which erroneously listed an Mw proxy = 8.7 based on mb from 3 stations. Mw proxy now deprecated and event listed in the supplementary file with magnitude quality flag = D. We are grateful to colleagues at USGS for pointing out this rogue magnitude.

Catalogue Overview, Version 9.0, 15 March 2022

On the 15th of March 2022, the version 9.0 of the ISC-GEM Catalogue was publicly released. The release marked the end of the fourth year of the Advancement Project .

During this year we added to the catalogue a) 922 earthquakes that occurred in 2018 and 5929 shallow earthquakes between 1976 and 2017 that have occurred within 50 km of coastline with Mw from GCMT between 5.0 and 5.5 b) 91 source mechanisms (in form of moment tensors and/or fault planes) from the literature for earthquakes between 1915 and 1989. 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.

We also improved the location and/or magnitude for 127 earthquakes as a result of the ISC Bulletin rebuild work (Storchak et al., 2017, 2020) and completion of the ISC-EHB dataset (Engdahl et al., 2020). 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 9.0 of the ISC-GEM Catalogue (about 49,000 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 (1904-2018).

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.