Fig.1: map showing the earthquakes listed in the version 7.0 of the ISC-GEM catalogue (about 39,400 earthquakes, see Fig.2). The symbols are plotted according to Agnew (2014) and colour coded according to the ISC-GEM depth.
On the 9th of April 2020, the version 7.0 of the ISC-GEM Catalogue was publicly released. The release marked the end of the second year of the Advancement Project .
During this year we added to the catalogue a) over 3,400 earthquakes during 1980-1990 and 2016. About 1260 of those earthquakes are continental events with magnitude ≤ 5.5; b) ~270 source mechanisms (in form of moment tensors and/or fault planes) from the literature for earthquakes between 1908 and 1994. 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 116 earthquakes as a result of the literature review (past and recent papers) and rebuild work (Storchak et al., 2017). 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.
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Fig.1: map showing the earthquakes listed in the version 7.0 of the ISC-GEM catalogue (about 39,400 earthquakes, see 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 (1904-2016).
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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 2016 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 1980-1990, 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. |