Catalogue Update Log

25 June, 2024: Version 11.0 released

Version 11.0 of the ISC-GEM Catalogue is the result of the 1st Year of the ISC-GEM Improvement Project that began in 2022. For Version 11.0 we have reassessed 1,678 earthquakes during 1964-1970 after adding station data, particularly to improve their surface wave magnitude (MS) estimation. As result of the data added during 1964-1970 from stations bulletins, 642 earthquakes that occurred in these years are listed for the first time in the catalogue. Furthermore, the catalogue has been extended to the end of 2020, which now includes 1581 earthquakes with Mw down to 5.0 globally. As in previous project years we continued to monitor new publications providing information on pre-digital earthquakes and revise existing ones. This is a summary of the individual updates following the literature review:

  • Revised the location about 100 km SSE for the 1906 earthquake in Slovakia (evid = 610326302) following the results of Nasir et al. (2020);

  • Revised the location about 1300 km NNW for a 1908 earthquake offshore Sumatra (evid = 16958004). The relocation now fits the macroseismic data in Martin et al. (2022);

  • Added direct Mw of 5.4 for the 1926 Jersey earthquake (evid = 909960) from the work of Baumont et al. (2023). The event now is listed in the main catalogue (previous Mw proxy based on our MS was 5.36 and had magnitude quality flag = D);

  • Relocated about 19 km NNW the 1947 Squillace basin earthquake (evid = 897852) after considering the results in Scolaro et al. (2024);

  • Updated the magnitude for a 1965 Vanuatu earthquake (evid = 857011) by replacing the Mw=7.7±0.4 from Brune and Engen (1969) with a Mw proxy of 7.2±0.2 based on our recomputed MS. We also have revised the depth, from 120 km to 50 km (fixed);

  • Reassociated the direct Mw=5.5 from literature (Doser, 1991) from evid 839881 to evid 832506. Evid 839881 has now a Mw proxy of 6.7±0.5.

21 March, 2023: Version 10 released

Version 10.0 of the ISC-GEM Catalogue is the result of the 1st Year of the ISC-GEM Improvement Project that began in 2022. It adds 18,576 globally distributed 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). Finally, we have updated the Mw for three earthquakes using recent results from the literature (see Lee and Engdahl, 2015; Di Giacomo and Storchak, 2022), as detailed below:

  • from Ortiz et al. (2022), evid = 897515 (1948 Anta earthquake, Argentina) has a direct Mw = 6.9 instead of MS-based Mw proxy = 7.0. Source mechanism added as well;

  • from Lin et al. (2021), evid = 608889849 and 608889850 (both occurred on 2016-05-28 in southwest Australia) have direct Mw = 5.16 and 5.26 instead of mb-based Mw proxy of 5.15 and 5.21, respectively. Source mechanisms added as well.

27 June, 2022: Version 9.1 released

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.

15 March 2022: Version 9.0 released

Version 9.0 of the ISC-GEM Catalogue is the result of the 4th Year of the Advancement Project that began in 2018. Version 9.0 adds 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. Such earthquakes have also been included in 2018 (305 out of 922 earthquakes). In addition, we added 91 direct Mw and source mechanisms from the literature by continuing the work of Lee and Engdahl (2015). 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).

Details of additional changes to the catalogue are listed below.

  • Events added or updated following a cross-check of the references in the Global Waveform‑Modelled Earthquake Catalog (v1.0, Wimpenny and Watson, 2020) and further review of the bibliographic search of Lee and Engdahl (2015):
  • Evid = 904826 (1934 Pahiatua earthquake, New Zealand) has been relocated about 80 km to the East with fixed depth of 15 km instead of 35 km;
  • from Holt et al. (1991), evid = 16957826 has a direct Mw = 7.1 and it is now listed in the main catalogue. Also, the location has been updated ~670 km NNE of its previous epicentre. Evid 864048, 849911, 850150, 843878, 843964, 832279, 798878, 785990, 785149, 785173, 774238, 733279, 729597, 726983, 726989, 714822, 714844, 714906, 712326, 710697 have now direct Mw instead of Mw proxies. All magnitude changes are within 0.5 magnitude units. Source mechanisms added as well;
  • from Doser (1994), evid = 913953 has a direct Mw = 6.6 instead of MS-based Mw proxy = 7.0. Source mechanism added as well;
  • from Sagiya (2003), evid = 913339 has a direct Mw = 6.1 instead of MS-based Mw proxy = 6.45;
  • from Katsumata (2000), evid = 912384 has a direct Mw = 6.43 instead of MS-based Mw proxy = 6.41. Source mechanism added as well. In addition, the location has been updated with depth = 60 km instead of 35 km and epicentre 73 km to the East;
  • from Aoudia and Meghraoui (1995), evid = 911991 has a direct Mw = 6.0 instead of MS-based Mw proxy = 5.6. Location revised 45 km North of previous epicentre;
  • from Somerville (1980), added direct Mw for evid 888741 and 857299. Evid 888741 is now listed with direct Mw = 6.3 instead of mb-based Mw proxy = 7.5, whereas evid 857299 has direct Mw = 5.66 instead of mb-based Mw proxy = 5.66. Source mechanisms added as well;
  • from Doser (1991), evid = 885127 has a direct Mw = 6.2 instead of MS-based Mw proxy = 6.4. Source mechanism added as well;
  • from Miyajima and Abe (1982), evid = 877175 has direct Mw = 7.02 instead of MS-based Mw proxy = 7.07. Source mechanism added as well;
  • from Pelayo and Wiens (1989), 7 Scotia Sea earthquakes, evid 17291785, 854160, 804921, 794605, 787022, 764307, 720989, have direct Mw instead of proxy Mw. All magnitude changes are within 0.3 magnitude units except for evid 794605 (direct Mw = 6.79 instead of proxy Mw = 7.18) and evid 17291785 (direct Mw = 6.99 instead of proxy Mw = 6.51). Source mechanisms added as well;
  • from Bergman and Solomon (1988), evid = 717216 has direct Mw = 5.88 instead of proxy Mw = 5.78. Source mechanism added as well;
  • from Moore et al. (2000), evid 864342 has an updated direct Mw = 7.0 instead of a direct Mw = 7.6 from Furumoto and Nakanishi (1983). Source mechanism updated as well. Evid 831453 has an updated direct Mw = 6.7 instead of a direct Mw = 7.0 from Brune and Engen (1969). Source mechanism added as well. Evid 847789, 835008, 808108, 774029, 724030, 405520 have direct Mw instead of MS-based Mw proxy. All magnitude changes are within 0.4 magnitude units except for evid 847789 that has Mw = 7.0 instead of 6.1. Source mechanisms added as well;
  • from Bergman and Solomon (1985), evid = 853506 has direct Mw = 5.79 instead of mb-based Mw proxy = 5.53 and evid = 757773 has direct Mw = 5.65 instead of MS-based Mw proxy = 5.69. Source mechanisms added as well;
  • from Bernard et al. (2000), evid 844042, 844044, 731510, 731564 have direct Mw instead of Mw proxy. Evid 844044 has direct Mw = 6.2 instead of 6.9 and evid = 844042 has Mw = 5.8 instead of 6.2. Source mechanisms added as well;
  • from Seno and Gonzalez (1987), evid 906320, 800688, 727642 have direct Mw instead of proxy Mw. All magnitude changes within 0.3 magnitude units. Added evid 833123 and 806245 with direct Mw = 5.3 and 5.2, respectively, Source mechanisms added as well;
  • from Langston and Franco-Spera (1985), evid = 828314 has direct Mw = 5.0 instead of mb-based Mw proxy = 5.34. Source mechanism added as well;
  • from Engeln et al. (1986), 14 Atlantic mid-oceanic ridge earthquakes, evid 855152, 842636, 825333, 815166, 792739, 789478, 780929, 774329, 757687, 754461, 724816, 722637, 712675, have direct Mw instead of proxy Mw. All magnitude changes are within 0.3 magnitude units except for evid 815166 (direct Mw = 6.58 instead of proxy Mw = 6.21) and evid 855152 (direct Mw = 6.07 instead of proxy Mw = 5.51). Added also evid 855117, 813366, 805277, 780311 with direct Mw between 5.7 and 5.9. Source mechanisms added as well;
  • from Bergman (1986), evid 818179, 816646, 773683, 768533, 761994, 749280, 735629, 710523 have direct Mw instead of proxy Mw. All magnitude changes are within 0.3 magnitude units except for evid 749280 (direct Mw = 5.32 instead of mb-based proxy Mw = 5.68). Source mechanisms added as well. In addition, evid = 761994 (1973 Honomu earthquake, Hawaii) has been relocated 8 km to the South and with fixed depth of 45 km instead of 10 km; direct Mw also updated to 6.38 instead of the direct Mw of 6.50 from Richardson and Solomon (1977). Source mechanism added as well;
  • from Nábělek et al. (1987), evid 710563 and 700781 have direct Mw instead of mb‑based Mw proxy. Magnitude changes within 0.2 magnitude units. Source mechanisms added as well;
  • from Alptekin et al. (1986), evid = 816634 has direct Mw = 6.33 instead of MS-based Mw proxy = 6.31. Source mechanism added as well;
  • from Seno (1987), added evid = 787875 with direct Mw = 5.2. Source mechanism added as well;
  • from Huang and Solomon (1987), evid = 578576 has a direct Mw = 5.64 instead of MS-based Mw proxy = 5.69. Source mechanism added as well;
  • from Bergman and Solomon (1988), evid 874380, 804847, 794709, 765901, 714044 has an updated direct Mw instead of direct Mw from Muller (1983). All magnitude changes are within 0.4 magnitude units and source mechanisms updated as well. Evid 872348 has an updated direct Mw = 6.4 instead of direct Mw = 6.9 from Wyss (1970) and source mechanism added;

    • Updates following the review done in the Rebuild project (Storchak et al., 2017, 2020) and/or results in the recent literature:

  • following the results shown in Morozov et al. (2021), we revised the location of 11 earthquakes (evid 909350, 909503, 909504, 909505, 909506, 909507, 909508, 909515, 909516, 909518, 909527) belonging to the 1927 Crimea sequence. The epicentres moved between 8 and 70 km;
  • re-associated the Mw from bibliography from evid 854555 to 854556. The former is now listed in the Supplementary catalogue;
  • revised the location and/or magnitude of 127 earthquakes that occurred between 1964 and 2009. The location quality is improved for most of those earthquakes, and most notably, improvements in magnitude result in 35 earthquakes being listed in the main catalogue instead of the supplement;

    • Additional updates:

  • Evid = 913645 relocated about 65 km to the East and with depth of 15 km instead of 35 km. This earthquake is interpreted as a foreshock of evid 913647. The two earthquakes are now 23 km apart instead of 85 km. We are grateful to Ana Milena Sarabia for making us revise the location of the foreshock;
  • Evid = 911427 is now listed in the main catalogue after obtaining an MS-based Mw proxy = 6.2 after adding surface amplitudes from stations UCC (Uccle) and PUL (Pulkovo);
  • Evid = 827285 (1968 Belice, Sicily, mainshock) has a MS-based Mw proxy= 6.07 in place of the direct Mw = 6.4 from North (1977);
  • Added evid 814965 (1968-11-09 Southern Illinois earthquake, direct Mw=5.3 from Herrmann, 1979) after digitizing station data in the teleseismic distance range originally missing in the ISC Bulletin;
  • Updated depth for evid 650671, 422192, 430129, 897984 to 17.5, 20, 11 and 15 km, respectively. Originally the depth was fixed at a default value of 35 km.


6 April, 2021: Version 8.0 released

Version 8.0 of the ISC-GEM Catalogue is the result of the 3rd year of the Advancement Project that began in 2018. Version 8.0 adds 543 earthquakes that occurred in 2017 with magnitude 5.5 and above plus continental earthquakes with magnitude 5.0-5.5. For the period 1991-1999, we added about 1900 earthquakes that include both continental events with magnitude 5.0-5.5 and events around the magnitude cut-off threshold of 5.5 that were not selected before. In addition, we added 448 source mechanisms from the literature by continuing the work of Lee and Engdahl (2015). 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 of additional changes to the catalogue are listed below.

  • 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 toRudolf Widmer-Schnidrig of the Black Forest Observatory for making this possible). We digitized the readings containing amplitude and period measurements of surface waves following the same procedures described in Di Giacomo et al. (2015). Overall, the data added is concentrated in the mid-1920s to early 1930s, and the largest contributions come from stations ALI, ALM, MAL and TOL (Alicante, Almeria, Malaga and Toledo, respectively) of the Spanish network. Notable additions are also readings from non-European stations, such as USA stations CHK and HON (Chicago and Honolulu, respectively) as well as Japanese stations KOB and SUM (Kobe and Sumoto, respectively). Only station Sofia (SOF, Bulgaria), has been added in the early 1940s. In total, we added ~1900 readings from 30 stations associated to ~900 earthquakes in the ISC-GEM Catalogue and 17 newly selected earthquakes that were not included in the catalogue before. The most important effect in the increase of number of stations to re-compute magnitude is the gain of 45 new MS values for earthquakes that we did not have any. As a result, 36 earthquakes previously listed in the supplementary file now are listed in the main catalogue (9 earthquakes have uncertain magnitude and are still listed in the Supplementary file). In general, marginal changes affect the MS of the earthquakes with revised MS, the only exception being event 907055. This event is part of an aftershock sequence in the Bougainville – Solomon Islands region during October 1931 and we observe a large change in MS from 7.05 to 5.38 because two readings, one from UPP (Uppsala, Sweden) and the other from Gottingen (GTT, Germany), were wrongly associated to evid 907055 instead of larger events close to evid 907055. After reassociating UPP and GTT readings to the correct events, we obtain a new MS of 5.4 for evid 907055 thanks to the readings added from SUM and KOB station bulletins.Another benefit of the data added from the bulletins of the University of Stuttgart regards the improvements in location (the readings added may also contain body-wave arrival times) for some earthquake. Indeed, we have updated the location flag from D to C for four earthquakes (evid 909834, 910109, 909037 and 907067) thanks to the additional arrival times we have digitized whilst searching for surface wave data. Of the 900 reprocessed earthquakes only 11 earthquakes (evid 912640, 911049, 910668, 911221, 910345, 908669, 908792, 910670, 909834, 909037 and 907067) were affected by significant changes in epicentre (more than 50 km) and/or depth (more than 20 km). On top of the events already listed in the catalogue, we also added data for earthquakes that were not selected before due to lack of amplitude stations. As a result of this additional effort, we have added to the catalogue 17 events. We have obtained magnitude for the first time for evid 912005, 912028, 910419, 909879, 909965 (the largest event is an MS 6.5 in Northern Xinjiang in 1922, evid 912028), whereas evid 910549 and 906674 have no magnitude and evid 909751, 909935, 906908, 905422 and 905423 have highly uncertain magnitude. Finally, evid 911824, 910660, 909793, 909954 and 907104 have poor location (quality flag for location set to D, hence these events are listed in the supplementary file of the catalogue).
  • Updated location/depth/magnitude for the following earthquakes:
  • from Cara et al. (2017), evid = 610326285 has a direct Mw = 5.3 instead of a proxy Mw = 5.8;
  • from Okal (1992), evid = 16957884 has a direct Mw = 8.45±0.3 instead of a proxy Mw = 8.75±0.7. The seismic moment of Okal (1992), although adjusted and based on a single station (UPP), is in line with the Mw estimations of 8.3-8.6 from more recent literature. This Mw value is also consistent with results from tsunami studies (see references in the Event Bibliography);
  • from Ayele and Kulhánek (2000), evid 16957915, 16958124 and 908452 have direct Mw = 6.5, 6.9 and 6.7 instead of proxy Mw = 6.5, 7.3 and 6.9, respectively. The locations have also been updated in line with the results of Ayele and Kulhánek (2000): evid 16957915, 16958124, 908452 moved about 220 km to the East, 130 to NNW and 50 km to the West, respectively. Source mechanisms added as well;
  • from Huang et al. (1998), added direct Mw for evid 914265, 913894, 913818, 881210. All four deep events are not listed in the main catalogue with Mw between 6.3 and 7.6. Source mechanisms added as well;
  • Evid = 913877 has been relocated about 32 km to the West with fixed depth of 15 km instead of 35 km;
  • Evid 16958205 has been relocated about 43 km NNE taking into account the results in the literature. Its large aftershock, evid = 610326388, has also been relocated about 30 km NNE;
  • from Kulikova et al. (2016), evid = 16958134 has a direct Mw = 7.2 instead of a proxy Mw = 7.3. Source mechanism added as well;
  • Evid 912192 has been relocated about 124 km South with fixed depth of 65 km instead of 15 km;
  • from Ou et al. (2020), evid = 912687 has an updated direct Mw = 7.9 instead of direct Mw = 8.3 from Chen and Molnar (1977). Source mechanism added as well. The location has also been updated 35 km South of previous location after adding 33 body-wave arrival times from stations located in Germany;
  • from Doser et al. (2005), added direct Mw for evid 913947, 913793, 913579, 912920, 909422, 907465, 902017, 899948. Evid 913793 now is listed in the main catalogue with Mw = 6.8, whereas for the other seven events the magnitude change is within 0.1 or 0.2 magnitude units. Source mechanisms added as well;
  • from Doser et al. (1999), added direct Mw for evid 912127, 908156, 908161, 908162, 898072, 897342 and 874715. Evid 908161 has been relocated 40 km South and with fixed depth of 15 instead of 65 km. Evid 908156 and 898072 are now listed in the main catalogue with Mw = 6.25 and 6.13, respectively. The magnitude changes for the other events are all within 0.3 magnitude units but for evid 874715 (direct Mw = 5.6 instead of proxy Mw = 6.0). Source mechanisms added as well;
  • from Doser and Webb (2003), added direct Mw for evid ;913599, 906608, 900403, 898007, 887887 and 600678247. Evid 900403 has been relocated 100 km North and now is listed in the main catalogue with Mw = 5.5 The magnitude changes are all within 0.2 magnitude units. Source mechanisms added as well;
  • from Fernández-Arce and Doser (2009), evid = 910853 has a direct Mw = 6.65 instead of a proxy Mw = 7.13. The location of the event has also been updated taking into account the discussion in Fernández-Arce and Doser (2009) and references therein. The fixed depth is now 25 km (instead of 15 km) and epicentre about 56 km Southwest of previous location. Source mechanism added as well;
  • Evid = 903992 has been relocated 89 km SSW of previous location and fixed depth updated from 35 km to 15 km;
  • from Doser (1989a), added direct Mw for evid 910562, 904601, 904621, 898156, 882681 and 863737. The magnitude changes are within 0.3 magnitude units. Source mechanisms added as well;
  • from Fletcher and Christensen (1996), evid 903173, 898078 and 884131 have direct Mw = 7.12, 7.07, 6.80 instead of proxy Mw = 7.12, 7.15, 7.12, respectively. Source mechanisms added as well;
  • from Doser and Brown (2001), added direct Mw for evid 908754, 906081, 905539, 904918, 904995, 900071, 898216, 896889, 891130 and 872100. The latter is now listed in the main catalogue with Mw = 6.07. These events have occurred between 1928 and 1963 in the Prince William Sound, Alaska, region and have Mw between 6.0 and 7.0. The largest magnitude changes occur for evid = 904995 (direct Mw = 6.7 instead of proxy Mw = 6.0), evid 900071 (direct Mw = 6.9 instead of proxy Mw = 7.3) and evid = 891130 (direct Mw = 6.8 instead of proxy Mw = 6.4), whereas for the other six earthquakes the magnitude changes are within 0.15 magnitude units. Source mechanisms added as well;
  • from Coudurier-Curveur et al. (2020), evid = 895681 has an updated direct Mw = 8.7 instead of a direct Mw = 8.6 from Kanamori (1977). Source mechanism added as well;
  • Evid = 895647 is listed in the Main Catalogue after updating the depth to 15 km (instead of 125 km) that allowed us to obtain a proxy Mw = 5.8 based on MS from 15 stations;
  • Evid = 894262 has an updated proxy Mw = 6.9 instead of proxy Mw = 7.1. The new proxy Mw is based on MS from 27 stations instead of 10;
  • from Alvarado and Beck (2006), evid = 899270 and 893012 have direct Mw = 6.9 and 6.8 instead of proxy Mw = 7.2 and 6.5, respectively. Source mechanisms added as well;
  • from Doser (2005), added direct Mw for evid 904937, 900732, 900577, 899178, 893820, 891517, 890763, 886362, 875994, 872296, 872570. These events have occurred between 1934 and 1963 in the Kodiak Island region and have Mw between 5.9 and 6.7. The largest magnitude changes occur for evid = 900732 (direct Mw = 6.2 instead of proxy Mw = 6.6), evid 893820 (direct Mw = 6.45 instead of proxy Mw = 6.85) whereas for the other nine earthquakes the magnitude changes are within 0.3 magnitude units. Evid 900577 has also been relocated about 27 km S-SW of previous location and depth updated from 35 km to 90 km. Source mechanisms added as well;
  • from Okal and Saloor (2017), evid 897790 and 897857 have updated direct Mw = 7.7 and 7.6, respectively, instead of direct Mw = 7.0 from Doser and Webb (2003), and proxy Mw = 7.14, respectively. Also the locations have been revised following Okal and Saloor (2017) and references therein: evid = 897790 has the epicentre about 60 km NNE from previous location and fixed depth = 15 km (instead of 25 km); evid = 897857 has the epicentre about 68 km to the East from previous location;
  • from Doser (1990), evid 897809 has direct Mw = 6.45 instead of proxy Mw = 6.56. Source mechanism added as well;
  • from Başarır Baştürk et al. (2016), evid 873085 has an updated direct Mw = 6.14 instead of direct Mw = 6.2 from North (1977). Evid 904020 and 904023 have an updated direct Mw = 6.34 and 6.0, respectively, instead of proxy Mw = 6.37 and 6.35, respectively. Source mechanisms added as well;
  • from Melis et al. (2020), evid = 896705 as a direct Mw = 7.16 instead of a proxy Mw = 6.54. Source mechanisms added as well;
  • from Doser et al. (1999), added direct Mw for 17 earthquakes in the Prince William Sound region (evid 869987, 870100, 870148, 868333, 868342, 868414, 868951, 868977, 867811, 864430, 845076, 814226, 809082, 792985, 757785, 756140, 732776). The magnitude changes are all within 0.4 magnitude units but for evid = 868951 (direct Mw = 6.4 instead of proxy Mw = 5.75), evid 868333 (direct Mw = 6.42 instead of proxy Mw = 5.90) and evid 867811 (direct Mw = 5.67 instead of proxy Mw = 6.13). Source mechanisms added as well;
  • from Doser et al. (2002), added direct Mw for 18 earthquakes in the Kodiak island region (evid 870136, 868351, 868363, 868783, 865396, 856357, 853605, 851909, 851097, 848441, 848633, 824251, 797882, 796868, 757502, 750989, 738145, 738149). These events have occurred between 1965 and 1974 in the Kodiak Island region and the magnitude changes are all within 0.4 magnitude units. Source mechanisms added as well;
  • from Patton and Zandt (1991), added direct Mw for evid 875624, 851116, 829986, 824428, 818715, 724791 and 592538. The magnitude changes are within 0.5 magnitude units. Source mechanisms added as well;
  • from Assumpção and Araujo (1993), added direct Mw for evid 851422, 837096, 807188, 703930 and 654584. Evid 851422 is now listed in the main catalogue. The magnitude changes are all within 0.2 magnitude units but for evid = 654584 (direct Mw = 5.0 instead of proxy Mw = 5.5). Source mechanisms added as well;
  • from Frankel (1984), evid = 651770 has direct Mw = 4.9 instead of proxy Mw = 5.3;
  • from Webb and Anderson (1998), added direct Mw for evid 848946, 822768, 752113 and 727299. The magnitude changes are all within 0.2 magnitude units. Source mechanisms added as well;
  • from Wei and Chung (1993), evid 749631 and 458848 have direct Mw = 5.2 and 5.0, respectively, instead of proxy Mw = 5.3. Source mechanism added for evid 458848;
  • from Bent and Hasegawa (1992), evid 410206 has direct Mw = 5.0 instead of proxy Mw = 5.4. Source mechanisms added as well;
  • the direct Mw = 5.7 from Westaway (1990) for the 1974-09-04 Tripoli, Libya, event was erroneously associated to evid = 737146 instead of evid = 737147. Evid = 737146 has now a proxy Mw = 5.6 based on our re-computed mb;
  • from Doser and Vandusen (1996), added direct Mw for evid 909727, 904192, 901464, 881160, 908913, 899241, 887289 and 879338. The first four events were listed in the Supplementary catalogue and are now listed in the Main Catalogue with Mw between 5.9 and 6.6, whereas the last four events have Mw between 5.8 and 6.3 instead of proxy Mw between 5.8 and 6.5. Evid = 879338 has also been relocated about 9 km N-NE of previous location. Source mechanisms added as well;
  • Evid = 909960 has an updated location about 29 km NNW of previous one and depth = 10 km instead of 15 km. The updated location is consistent with the results of Amorèse et al. (2020). Our proxy Mw = 5.0, although within the Mw range of 5.0-5.5 estimated by Amorèse et al. (2020), is based on a poorly constrained MS, and the event is still listed in the Supplementary catalogue;
  • Evid 895280, 895549 and 895717 have updated Mw proxy = 6.8, 6.6 and 6.3 instead of 6.7, 6.3 and 6.4, respectively, after MS recomputations thanks to amplitude reading added from European stations;
  • from Doser (1987), evid 881629 and 882314 have direct Mw = 5.7 and 5.5 instead of proxy Mw = 6.0 and 5.6, respectively. Evid = 882316., previously in the supplementary catalogue, has now a direct Mw = 5.4. Source mechanisms added as well;
  • from Doser et al. (1997), added direct Mw for evid 885173, 799398, 796590, 796787 and 796899. These events have occurred between 1958 and 1970 in the Yakutak block, Alaska, and the magnitude changes are all within 0.3 magnitude units. Source mechanisms added as well;
  • from Okal (2012), evid 903272 and 899940 have direct Mw = 6.9 and 7.4 instead of proxy Mw = 6.9 and 7.0, respectively. Source mechanisms added as well;
  • from McCaffrey (1993), evid = 901916 has direct Mw = 7.83 instead of proxy Mw = 7.95;
  • from Bent (2002), evid = 905919 has an updated direct Mw = 7.44 instead of a direct Mw = 7.7 from Stein et al. (1979). Source mechanisms added as well;
  • from Doser (1988), evid 904767 has direct Mw = 6 instead of proxy Mw = 6.5 and source mechanism added. Evid 904766 and 899958, previously in the supplementary catalogue, have direct Mw = 5.6 and are now listed in the main catalogue;
  • from Doser (1989b), evid 904837 and 904838 have direct Mw = 6.56 and 5.86 instead of proxy Mw = 6.55 and 6.05, respectively. Source mechanisms added as well;
  • from Abe (1978), evid = 904853 has a direct Mw = 5.25 instead of a proxy Mw = 5.57. Source mechanism added as well;
  • from Cassidy and Bent (1993), evid = 901383 has a direct Mw = 6.3 instead of a proxy Mw = 6.23. Source mechanism added as well;
  • from Baker et al. (1997), evid 883288 and 754132 have direct Mw = 6.74 and 5.8 instead of proxy Mw = 6.65 and 5.78, respectively. Evid 873781, 868700, 855169 and 835092 have updated direct Mw = 5.5, 5.7, 6.1 and 5.9, respectively, instead of direct Mw = 5.7, 6.0, 6.3 and 6.2, respectively, from North (1977). Source mechanisms added as well;
  • from Anderson et al. (1993), added direct Mw for evid 857649, 848647, 822588, and 817350. These events have occurred between 1964 and 1971 in South Island, New Zealand, and the magnitude changes are all within 0.2 magnitude units. Source mechanisms added as well;
  • from Malavé and Suárez (1995), evid 815159 has direct Mw = 5.9 instead of proxy Mw = 6.1. Source mechanisms added as well;
  • from Kanamori et al. (2019), evid = 879136 has an updated direct Mw = 9.55 instead of direct Mw = 9.6 from Cifuentes and Silver (1989). A source mechanism with strike-slip component (rake = 140°) has also been added. However, as noted by Kanamori et al. (2019), other solutions are possible;
  • from Kanamori and Rivera (2017), evid = 879416 has an updated direct Mw = 7.7 instead of a direct Mw = 7.8 from Kanamori and Stewart (1976);
  • from Huang et al. (1986), evid = 874839 and 774087 have direct Mw = 5.8 and 5.7 instead of a proxy Mw = 5.76 and 5.42, respectively. Source mechanisms added as well;
  • from Wallace et al. (1981), evid = 875249 and 731708 have direct Mw = 5.8 and 6.0 instead of proxy Mw = 5.9 and 6.0, respectively. Source mechanisms added as well;
  • from Kiratzi and Langston (1989), evid = 773147 has direct Mw = 6.21 instead of proxy Mw = 6.27. Source mechanism added as well;
  • from Taymaz et al. (1991b), evid = 866809 and 784837 have direct Mw = 5.8 and 6.58 instead of a proxy Mw = 5.82 and 6.86, respectively. Source mechanisms added as well;
  • from Papadimitriou (1993), evid = 806820, 769484 and 754939 have direct Mw = 5.65, 6.2 and 5.7, respectively, instead of proxy Mw = 5.55, 6.4 and 5.9, respectively. Source mechanisms added as well;
  • from Taymaz et al. (1990), evid 857618, 847303 and 807959 have updated direct Mw = 6.0, 5.5, 6.0, respectively, instead of direct Mw = 6.2, 6.0 and 6.1, respectively, from North (1977). Evid 724259 has direct Mw = 5.57 instead of a proxy Mw = 5.54. Source mechanisms added as well;
  • from Lyon-Caen et al. (1988), evid = 858076 has an updated direct Mw = 5.5 instead of direct Mw = 6.1 from North (1977). Source mechanism added as well;
  • from Kao et al. (2000), added direct Mw for 17 earthquakes in the Luzon arc – Taiwan region (evid 864850, 858396, 843541, 837387, 826743, 804142, 784309, 779458, 776783, 777303, 772321, 769785, 763903, 747879, 735580, 683487, 145772). The magnitude changes are all within 0.4 magnitude units but for evid = 826743 (direct Mw = 6.66 instead of proxy Mw = 7.14), evid 769785 (direct Mw = 5.85 instead of proxy Mw = 6.36) and evid 843541 (direct Mw = 5.63 instead of proxy Mw = 6.19). Source mechanisms added as well;
  • Evid = 939317 has an updated proxy Mw = 5.7 based on mb instead of proxy Mw = 6.3 based on MS;
  • from Morelli et al. (2000), evid = 1047337 has an updated direct Mw = 5.6 instead of a proxy Mw = 5.8. Source mechanisms added as well;
  • from Craig et al. (2011), evid 1675144 has an updated direct Mw = 5.2 instead of a proxy Mw = 5.6. Source mechanisms added as well;
  • from Chi and Dreger (2004), evid 1656084 and 1656086 have updated direct Mw = 5.8 and 6.2, respectively, instead of proxy Mw = 6.3 and 6.4, respectively. Source mechanisms added as well;
  • from Fan et al. (1994), evid 776886 has an updated direct Mw = 5.7 instead of a proxy Mw = 5.7. Evid 738538 has an updated direct Mw = 7.0 instead of direct Mw = 7.1 from Jackson et al. (1979). Source mechanisms added as well;
  • from Spindler et al. (1997), evid 680306 and 679932 have direct Mw = 5.44 and 5.42 instead of proxy Mw = 5.54 and 5.48, respectively. Source mechanisms added as well;
  • from Taymaz et al (1991a), evid 858461, 826342 and 810456 have updated direct Mw = 6.0, 7.0, 5.7, respectively, instead of direct Mw = 6.1, 7.2 and 5.8, respectively, from North (1977). Source mechanisms added as well;
  • from Yılmaztürk and Burton (1999), evid 784339, 782114, 780154, 730797 have updated direct Mw = 6.3, 5.8, 5.5, 5.4 respectively, instead of proxy Mw = 6.2, 5.3, 5.4, 5.5. Source mechanisms added as well;
  • from Taymaz and Price (1992), evid = 784361 has an updated direct Mw = 5.5 instead of a proxy Mw = 5.7. Source mechanism added as well;
  • from McMullen (1985), evid = 776904 has an updated direct Mw = 5.8 instead of a proxy Mw = 5.9. Seismic moment and source mechanism from Fujita et al (1990);
  • from Kao and Chen (1995), added direct Mw for 17 earthquakes in the Kuril-Kamchatka arc (evid 864902, 852862, 853361, 847380, 847389, 846123, 826015, 804095, 800341, 779780, 777414, 770242, 754242, 737585, 731548, 728825, 724162). The magnitude changes are all within 0.3 magnitude units but for evid = 847380 (direct Mw = 5.49 instead of proxy Mw = 6.17) and evid 800341 ((direct Mw = 5.13 instead of proxy Mw = 5.63). Source mechanisms added as well;
  • from Frederich et al. (1988), evid 771020 has a direct Mw = 5.3 instead of a proxy Mw = 5.7. Source mechanism added as well;
  • from Hatanaka and Takeo (1989), evid = 730371 has a direct Mw = 6.3 instead of a proxy Mw = 6.4. Source mechanism added as well;
  • from Wiens and Stein (1984), evid = 864472, 829595, 723396 and 709472 have direct Mw = 5.86, 5.79, 5.71, 5.57 instead of a proxy Mw = 5.67, 5.71, 5.71 and 5.89, respectively. Source mechanisms added as well;
  • from Buforn et al. (1988), evid = 864498 and 808624 have direct Mw = 5.85 and 5.34 instead of a proxy Mw = 5.65 and 5.58, respectively. Evid = 790313 has an updated direct Mw = 5.57 instead of a direct Mw = 5.9 from Muller (1983);
  • from Parvez and Ram (1996), evid = 863756 has direct Mw = 6.6 instead of proxy Mw = 6.8
  • from Huang and Solomon (1988), evid = 845209 and 751094 have direct Mw = 5.67 and 5.9 instead of a proxy Mw = 5.55 and 5.67, respectively. Source mechanisms added as well;
  • from Pinar et al. (1996), evid = 833573 has an updated direct Mw = 7.3 instead of a direct Mw = 7.4 from Stewart and Kanamori (1982). Source mechanisms added as well;
  • from Abers et al. (1997), added direct Mw for evid 830123, 826964, 799772, 788524, 760101, 760115, 736783 and 708658. The magnitude changes are all within 0.2 magnitude units. Source mechanisms added as well;
  • from Baker et al. (1993), evid = 821091 and 785381 have direct Mw = 5.5 and 5.2 instead of a proxy Mw = 5.39 and 5.36, respectively. Source mechanisms added as well;
  • from Tréhu et al. (1981), evid 797091 has a direct Mw = 5.7 instead of a proxy Mw = 5.55;
  • from Walker et al. (2003), evid = 816697 has a direct Mw = 5.5 instead of a proxy Mw = 5.53. Source mechanisms added as well;
  • from Suarez et al. (1983), evid = 813767 and 779337 have direct Mw = 5.8 and 5.6 instead of a proxy Mw = 5.5 and 5.7, respectively. Source mechanisms added as well;
  • Evid = 777750 and 752200 have an updated direct Mw = 7.62 and 7.04 instead of 7.59 and 6.72, respectively, after correcting typos in the seismic moment originally inserted from Zakharova and Chepkunas (1977);
  • from Eyidogan and Jackson (1985), evid 811616 and 798506 have an updated direct Mw = 6.8 and 7.23, respectively, instead of direct Mw = 6.7 and 6.9, respectively, from North (1977). Evid = 796798 has direct Mw = 5.5 instead of proxy Mw = 5.56. Source mechanisms added as well;
  • from Kebede et al. (1989), evid 811667 and 809619 have direct Mw = 5.8 and 5.7 instead of proxy Mw = 6.1 and 5.4, respectively. Source mechanisms added as well;
  • from Grimison and Chen (1986), evid = 804189 has an updated direct Mw = 6.0 instead of a direct Mw = 6.1 from North (1977). Source mechanism added as well;
  • from Wang et al. (1991), evid = 715117 has a direct Mw = 5.8 instead of a proxy Mw = 6.1. Source mechanisms added as well;
  • from Pondrelli et al. (2001), evid 713751, 713914, 708347, 708348 and 708560 have direct Mw instead of proxy Mw. The magnitude changes are between -0.1 and -0.24 magnitude units. Source mechanisms added as well;
  • from Louvari et al. (2001), evid = 534670 has an updated direct Mw = 5.2 instead of a proxy Mw = 5.55. Source mechanism added as well;
  • from Kiratzi and Louvari (2003), evid = 502314 has an updated direct Mw = 5.3 instead of a proxy Mw = 5.3. Source mechanism added as well;
  • from Pondrelli et al. (1999), evid 391124 has an updated direct Mw = 5.2 instead of a proxy Mw = 5.9. Source mechanism added as well;
  • from Ghose et al. (1998), evid = 291467 has a direct Mw = 5.9 instead of a proxy Mw = 6.3. Source mechanism added as well;
  • from Tape et al. (2015), evid = 1742778 has a direct Mw = 4.9 instead of a proxy Mw = 5.2. Source mechanism added as well;
  • from Yolsal-Çevikbilen and Taymaz (2012), evid = 7159973 has direct Mw = 5.53 instead of a proxy Mw = 5.55. Source mechanism added as well;
  • from Donner et al. (2013), evid = 7349696 has a direct Mw = 5.1 instead of a proxy Mw = 5.1. Source mechanism added as well;
  • from Minson et al. (2007), evid = 1737488 has an updated direct Mw = 5.3 instead of a proxy Mw = 5.6. Source mechanism added as well;
  • Evid = 1738466 has an updated proxy Mw = 5.6 based on mb instead of proxy Mw = 6.2 based on MS;
  • from Stich et al. (2003), evid 1741740 has a direct Mw = 5.1 instead of proxy Mw = 5.1. Source mechanism added as well;
  • from Ross et al. (2015), evid 2298998 has a direct Mw = 5.0 instead of proxy Mw = 5.3. Source mechanism added as well;
  • from Sharma et al (2014), evid = 12776554 has a direct Mw = 5.1 instead of proxy Mw = 5.3;
  • from Zheng et al. (2020), evid = 15742574 has a direct Mw = 6.3 instead of proxy Mw = 6.7. Source mechanism added as well;
  • from Martín et al (2015), evid 608001961 has a direct Mw = 5.0 instead of proxy Mw = 5.2. Source mechanism added as well;
  • from Doser et al. (2002), added evid = 864199 and 738167 with both direct Mw = 5.7. Source mechanisms added as well;
  • from Huang and Solomon (1988), added evid = 824131 and 771529 with direct Mw = 5.5 and 5.7, respectively. Source mechanisms added as well;
  • from Hashizume (1973), added evid = 788828 with direct Mw = 5.0. Source mechanism added as well;
  • from Buforn et al. (1988), added evid = 789668, 773446 and 648716 with direct Mw = 5.52, 5.42 and 5.55, respectively;
  • from Anderson et al. (1993), added evid 869382 and 781200 with direct Mw = 5.85 and 5.7, respectively. Source mechanisms added as well;
  • from Webb and Anderson (1998), added evid 750014 and 735096 with direct Mw = 5.8 and 5.4, respectively. Source mechanisms added as well;
  • from Hasegawa et al. (1979), added evid = 727630 with direct Mw = 5.4. Source mechanism added as well;
  • from Patton and Zandt (1991), added evid 875624 and 872679 with direct Mw = 5.2 and 5.0, respectively. Source mechanisms added as well. Deleted evid 636282 and 646154 after considering their direct Mw = 4.7 and 4.4, respectively. These events had proxy Mw = 5.2 and 5.3, respectively;
  • from Doser and Smith (1982), added evid 863670, 849333 and 761535 with direct Mw between 5.9 and 5.2;
  • from Abe (1978), added evid = 709966 with direct Mw = 5.5. Source mechanisms added as well;
  • from Bent and Hasegawa (1992), added evid 802630, 498660, 450613 and 410102 with direct Mw 5.0-5.1. Source mechanisms added as well;
  • from Pondrelli et al. (1999), added evid 540706 and 414569 with direct Mw = 5.1. Source mechanisms added as well;
  • deleted evid 853275 and 759364 after considering the direct Mw = 4.6 and 4.5, respectively, by Hermann (1979). Both events were listed with proxy Mw = 5.1;
  • from Imprescia et al. (2012), added evid = 608518 with direct Mw = 5.0. Source mechanism added as well. Deleted evid 558893 after considering the direct Mw = 4.8. The event was listed with proxy Mw = 5.25;
  • deleted evid 601551788 and 601561357 after considering the direct Mw = 4.7 and 4.8, respectively, by Donner et al (2015). The events were listed with proxy Mw = 5.2 and 5.3, respectively;
  • from Stich et al. (2003), added evid 551519, 484527 and 412598 with direct Mw = 5.0. Source mechanisms added as well;
  • Evid 13825954 has been moved to the Supplementary catalogue as its proxy, based on mb instead of MS, has large uncertainty. The MS was erroneously obtained from readings that belong to close event = 14092590 (Mw = 7.8 from GCMT);
  • deleted evid 17308392 as it has been merged with evid 798256;
  • deleted evid 1656082 as it has been merged with evid 1718616;
  • deleted evid 11906317 as, after reassessment along with close event 12696659, it does not meet the selection criteria of the ISC-GEM Catalogue;
  • deleted evid 16874517 as it has been merged with evid 16718055;
  • re-associated the GCMT solution from evid 181596 to 181597;
  • reassessed the Mw proxy for 26 earthquakes that occurred between 1981 and 1999. For ten events (evid 629928, 626279, 562542, 362906, 341121, 185730, 137617, 102775, 99991, 85331) the new Mw proxy is based on mb instead of MS and the magnitude changes are within 0.5 magnitude units but for evid 99991, 626279 and 629928, where the magnitude is between 0.7 and 0.8 magnitude units smaller than previous values. For the other 16 events (evid 539698, 529109, 517380, 488638, 480644, 446348, 443059, 428578, 386064, 347624, 334035, 322180, 322901, 260735, 940369, 1655244) the Mw proxy is based on recomputed MS and the magnitude changes are within 0.3 magnitude units.

  • Additional updates:
    •
  • added evid = 908215 with proxy Mw = 5.9;
  • evid 604041862, 609948332, 605130587, 605642941, 605737143 have updated proxy Mw based on mb instead of MS. The magnitude changes are between 0.2 and 0.4 magnitude units.


9 April, 2020: Version 7.0 released

Version 7.0 of the ISC-GEM Catalogue is the result of the 2nd year of the Advancement Project that began in 2018. Version 7.0 adds 595 earthquakes that occurred in 2016 with magnitude 5.5 and above plus continental earthquakes with magnitude 5.0-5.5. For the period 1980-1990, we added 2836 earthquakes that include both continental events with magnitude 5.0-5.5 and events around the magnitude cut-off threshold of 5.5 that were not selected before. In addition, we added 273 source mechanisms from the literature by continuing the work of Lee and Engdahl (2015). 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 of additional changes to the catalogue are listed below.


  • We thank Max Suter for pointing out papers with direct estimations of M0 (hence of Mw) for the following events:

    • from Doser and Rodriguez (1993), evid = 908949 (1928-11-01 Parral earthquake) has a direct Mw = 6.27 in place of a proxy Mw = 6.47 and source mechanism added;

    • from Doser (1987), evid = 906944 (1934-08-16 Valentine earthquake) has a direct Mw = 6.28 in place of a proxy Mw = 6.51 as well as a source mechanism;

    • from Suárez (2000), evid 882734 and 837720 have direct Mw = 6.4 and 5.62 in place of proxy Mw =6.36 and 5.86, respectively, and source mechanisms added;

  • Updated location/depth/magnitude for the following earthquakes:

      • from Martin et al. (2019), evid = 16957943 (1907-01-04 off coast Sumatra earthquake) has an updated direct Mw = 8.2 instead of a direct Mw = 7.8 from Kanamori et al. (2010). Event location also updated about 150 km Eastward (from lat = 2.42, lon = 94.26, depth = 15 km to lat = 2.68, lon = 95.53, depth = 25 km). The revised location is in line with the results of Martin et al. (2019) and their interpretation of this large earthquake;

      • from Anderson et al. (1989), added direct Mw for eight major earthquakes (evid 16957987, 16957988, 16958175, 913745, 908552, 908823, 908920, 905294) near the coast of Guerrero, Oaxaca and Jalisco (Mexico). The magnitude changes are in range ±0.3 units. As a result, evid = 16957988 now is listed in the Main catalogue. In addition, for evid 16957987 and 16957988 the location has been revised 170 and 300 km to the South, respectively, and depth from 80 and 70 km, respectively, to 25 km;

      • Evid = 16958007 (1908-12-12 Myanmar earthquake) has an updated location (about 29 km NNE) after adding arrival times from station ZKW and following a revision of the event after Di Giacomo and Dewey (2019);

      • Evid = 912683 has been relocated 350 km South-west and depth (fixed) also updated from 15 km to 25 km. We thank Víctor García for pointing out the mis-location of this event;

      • Evid 908489 and 908604 have an updated fixed depth of 80 km in place of depths of 15 km and 35 km, respectively. The locations moved about 35 and 87 km to the West for evid 908489 and 908604, respectively. Depth and location changes have been done taking into account the results of Jimenez and Ponce (1978);

      • from Iosif et al (1979), four intermediate-depth earthquakes (evid 908373, 904861, 901664, 899085) in the Vrancea region have direct Mw. As a result, these four events are now listed in the Main catalogue;

      • from Bent (1996), evid = 904623 has a direct Mw = 6.17±0.2 instead of proxy Mw = 6.27±0.2 and source mechanism added;

      • from Bent and Helmberger (1991), three earthquakes in Southern California have direct Mw: evid 903010 and 900505 have Mw = 6.0 and 6.28 in place of proxy Mw = 6.1 and 6.5, respectively, whereas evid = 900506, previously in the Supplementary catalogue, is now listed in the Main catalogue with Mw =6.05 and an updated location about 80 km to the North;

      • evid = 901696 (1940-11-10 Vrancea earthquake) has an updated depth of 150 km instead of 90 km and location ~11 km to the West. The direct Mw = 7.8±0.4 from Iosif et al. (1979) has been updated with a direct Mw = 7.74±0.3 from Oncescu and Bonjer (1997) and source mechanism added. The depth update is in line with the interpretation of the event by Oncescu and Bonjer (1997);

      • from Bent (1996), evid = 899531, previously in the Supplementary catalogue, has a direct Mw = 5.74±0.3 and source mechanism added;

      • Evid = 895445 (1950-05-21 Cusco earthquake) has been relocated with a depth of 10 instead of 100 km. The location moved ~12 km East. Not enough surface wave amplitude data is available to re-compute MS, therefore the event remains listed in the Supplementary Catalogue. We thank Léo Marconato for pointing out the shallow nature of this event;

      • from Muller (1983), evid = 864118 has a direct Mw =6.1±0.3 in place of proxy Mw = 5.57±0.4, and source mechanism added;

      • from Hanks (1971), evid = 875343 has a direct Mw =5.93±0.3 in place of proxy Mw = 6.16±0.35;

      • from Huang and Solomon (1987), evid 861576 and 844503 have an updated direct Mw = 5.8±0.2 and 5.70±0.2, respectively, instead of direct Mw = 6.3 and 6.0, respectively, from Tsai (1969). Source mechanism added for these two events;

      • from Kao and Chen (1994), evid 857484 and 766673 have direct Mw = 5.83 and 5.89, respectively, instead of proxy Mw = 5.7 and 5.65, respectively, and source mechanisms added as well;

      • from Forsyth (1973), evid 852214 has a direct Mw = 5.92±0.3 in place of proxy Mw = 6.21±0.31, and source mechanism added;

      • from Quittmeyer et al. (1984), evid 851175, 849961, 849991, 844039, 765097 have direct Mw in place of proxy Mw values as well as source mechanisms added. The largest magnitude change, from 6.45 to 6.09, occurs for evid = 849991. In addition, for evid = 849961 the direct Mw = 6.5±0.4 from Brune and Engen (1969) has been updated with a direct Mw = 6.28±0.3, and source mechanism added;

      • from Shudofsky (1985), evid 849441, 847524, 842196, 778530, 776171, 749720, 731621, 695596 have direct Mw in place of proxy Mw values as well as source mechanisms added. The largest magnitude change, from 5.53 to 5.07, occurs for evid = 849441;

      • from Bergman et al. (1984), evid 851845 and 665450 have direct Mw = 6.0 and 5.7, respectively, instead of proxy Mw = 5.6 and 5.7, respectively, and source mechanisms added as well;

      • from Quittmeyer and Kafka (1984), evid 849714, 770300, 770384, 736097 have direct Mw in place of proxy Mw values as well as source mechanisms added. The largest magnitude change, from 5.68 to 5.3, occurs for evid = 770300;

      • from Bergman and Solomon (1984), evid = 849961 has an updated direct Mw = 6.6±0.3 instead of a direct Mw = 6.42±0.2 from Forsyth (1973), and evid = 766025 has a direct Mw = 5.54 instead of proxy Mw = 5.59. Source mechanism added for these two events;

      • from Zhou et al. (1983), evid = 832769 has a direct Mw = 5.5 in place of proxy Mw = 5.83 as well as source mechanisms added;

      • from Chen and Forsyth (1978), evid = 829308 has an updated direct Mw = 6.3 instead of a direct Mw = 6.4 from Molnar and Wyss (1972), and evid = 769977 has a direct Mw = 6.2 in place of a proxy Mw = 6.2. Source mechanism added for both earthquakes;

      • from Chung (1993), evid = 798304 has a direct Mw = 5.36 in place of proxy Mw = 5.45 as well as source mechanisms added;

      • from Priestley et al. (1994), evid = 794114 has an updated direct Mw = 6.36 instead of a direct Mw = 6.7 from North (1977). Evid 787393 has an updated direct Mw = 5.67 instead of a proxy Mw = 5.85. Source mechanism added for both earthquakes;

      • from Abers and McCaffrey (1994), evid 777013 and 777043 have direct Mw (6.52 and 6.36, respectively) in place of proxy Mw (6.63 and 6.57, respectively) values as well as source mechanisms added;

      • from Abers and McCaffrey (1988), evid = 766904 has a direct Mw = 5.27 in place of proxy Mw = 5.79 as well as source mechanisms added;

      • from Nelson et al. (1987), evid = 774259 has a direct Mw = 5.34 in place of proxy Mw = 5.73 as well as source mechanisms added. Depth updated for evid 852398 and 598460 to 45 and 20 km, respectively, instead of 35 and 30.9, respectively;

      • from Chen and Molnar (1983), evid 757320 and 726312 have direct Mw (5.42 and 5.16, respectively) in place of proxy Mw (5.78 and 5.37, respectively) values as well as source mechanisms added;

      • from Zheng and Suzuki (1993), evid = 772832 (1972-06-24 Hindu-Kush region earthquake) has a direct Mw = 6.18 in place of a proxy Mw = 6.31 as well as source mechanism added;

      • from Singh and Wyss (1976), evid = 757676 (1973-08-28 Puebla earthquake) has a direct Mw = 7.05 and it is now listed in the main catalogue;

      • from Estabrook et al. (1992), evid = 647474 has a direct Mw = 5.24 in place of a proxy Mw = 5.52 as well as source mechanism added;

      • from Xu and Chen (1997), evid = 185689 has a direct Mw = 5.57 in place of a proxy Mw = 5.84 as well as source mechanism added;

      • from Bergman and Solomon (1984), added three earthquakes (evid 829246, 829275, 797139) in the Chagos Archipelago region with direct Mw in the range 5.4-5.65. Source mechanisms added as well;

      • from Quittmeyer and Kafka (1984), added five earthquakes (evid 872915, 823471, 814962, 756024, 760813) in Southern / off coast Pakistan with direct Mw in the range 5.0-5.7. Source mechanisms added as well;

      • from Forsyth (1973), added three earthquakes (evid 841093, 808352, 804292) in the East Pacific Rise / Galapagos with direct Mw in the range 5.7-6.2. Source mechanisms added as well;

      • from Shudofsky (1985), added evid = 830319 (1967-10-14 Kenya earthquake) with direct seismic moment (Mw = 5.17) as well as its source mechanism;

      • from Grimison and Chen (1988), added evid = 732326 (1975-02-15 Mozambique Channel earthquake) with direct seismic moment (Mw = 5.38) as well as its source mechanism;

      • from Petroy and Wiens (1989), added evid = 649381 (1980-03-11 South Indian Ocean earthquake) with direct seismic moment (Mw = 5.42) as well as its source mechanism;

      • updated the magnitude for three earthquakes (evid 395561, 395562, 395579) of the 1989 Afar sequence. The proxy Mw values are now based on mb instead of MS and in the range 5.3-5.5 instead of 6.1-6.6;

      • evid = 376632 has an updated proxy Mw = 6.02±0.66 based on mb instead of a proxy Mw= 7.13±0.34 based on MS;

      • For close events 234119 and 234120 we have re-associated the GCMT solution from 234119 to 234120; evid = 234119 is now listed in the Supplementary Catalogue as its proxy Mw based on mb has high uncertainty;

      • evid = 228648 has an updated proxy Mw = 5.8±0.58 based on mb instead of a proxy Mw= 6.60±0.26 based on MS;

      • Deleted three earthquakes (430746, 396787, 505928) from the Main catalogue and one from the Supplementary catalogue (evid = 167106); these events are close in time to larger earthquakes with magnitude originally overestimated;

      • evid = 1742706 has an updated proxy Mw = 5.5±0.34 based on mb instead of a proxy Mw= 6.1±0.2 based on MS;757676

      • evid = 1841012 has an updated proxy Mw = 6.2±0.62 based on mb instead of a proxy Mw= 6.71±0.43 based on MS;

      • evid = 7143736 has an updated proxy Mw = 5.3±0.3 based on mb instead of a proxy Mw= 5.8±0.4 based on MS;

      • evid = 11122103 has an updated proxy Mw = 5.32±0.26 based on mb instead of a proxy Mw= 6.23±0.25 based on MS;

 

7 March, 2019: Version 6.0 released

Version 6.0 of the ISC-GEM Catalogue is the result of the 1th year of the Advancement Project that began in 2018. Version 6.0 adds 623 earthquakes that occurred in 2015 with magnitude 5.5 and above plus continental earthquakes with magnitude 5.0-5.5. For the period 1964-1979 and 2000-2014, we added 7012 earthquakes that include both continental events with magnitude 5.0-5.5 and events around the magnitude cut-off threshold of 5.5 that were not selected before. In addition, we expanded the catalogue files to include also the nodal planes for GCMT events as well as source mechanism from the literature for those earthquakes with direct M0 from the bibliographic search of reliable seismic moments (see Lee and Engdahl, 2015). In total, we added 392 source mechanisms 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.

Additional changes to the catalogue are listed in detail below.

  • Added eight earthquakes between 1960 and 1963 (evid 878345, 876851, 874714, 874971, 875265, 872097, 872340, 873113). Two earthquakes (evid 872097, 873113) have direct Mw from bibliography. The other six earthquakes have proxy Mw based on our revised MS obtained after adding surface wave amplitude from individual bulletins. Four evid (78345, 876851, 87878345, 872340) have MS below 5, resulting in the events being listed in the Supplementary Catalogue.
  • Improved magnitude for six earthquakes occurred between 1956 and 1963 (evid 885232, 882347, 877400, 875806, 872357, 872989) thanks to the additional surface wave amplitude measurements gathered from stations in former Soviet Union. As a result, three earthquakes (evid 885232, 877400, 872357) moved from the Supplementary to the Main catalogue. For evid 885232 we also updated the depth to 35 km.

  • Updated location/depth for the following earthquakes:

    • evid = 16958143 has an updated depth of 560 km instead of 350 km and location ~165 km to the North in line with the results of Huang et al. (1998). The event has also a direct Mw = 7.38 from Huang et al. (1998) and is now listed in the main catalogue;
    • evid = 16958145 is an intermediate-depth event in Okal (1992) and the relocation has been updated by changing the depth from 35 km to 150 km; the epicentre also moved ~450 km NNW at the southern tip of the Kamchatka peninsula, which is closer to the original Gutenberg location. Note that the earthquake occurred in 1911 and the data available is sparse. Since the event with the location is too deep for MS calculation, it is now listed in the Supplementary catalogue;
    • evid = 913953 moved ~40 km N and depth changed from 15 to 10 km. The location fits better the results discussed by Doser (1994);
    • evid = 913126 and 911466 moved ~50 km to the East and ~130 km North-East, respectively, to better fit the results described by Doser (1992b). For evid = 911466 we have also added a direct Mw = 6.21 from Doser (1992b);
    • evid = 913230 moved ~145 km South in line with the results described by Stewart and Cohn (1979) and Okal et al. (2011);
    • evid = 910843 moved ~100 km North in line with the locations reported, e.g., in Badal et al. (2000) and Alasset and Meghraoui (2000, and references therein). The Mw proxy based on MS has also been updated to 5.46 after adding surface amplitudes from stations VIE, HAM and ESK;
    • evid = 910544 moved ~250 km NE and depth changed from 35 to 10 km. This change better fits the results discussed by Van Dusen and Doser (2000);
    • evid = 910569 (1925 Santa Barbara event) moved ~90 km E, in line with the findings of Hough and Martin (2018); still accordingly to Hough and Martin (2018), we updated the magnitude from a direct Mw = 6.8 by Hanks et al. (1975) to a proxy Mw of 6.56;
    • evid = 909759 has a depth of 100 km instead of 15 km and moves ~80 km to the South in line with the results of Okal and Bina (1994). The change of depth does not allow MS calculation and, therefore, evid = 909759 in now listed in the Supplementary catalogue; in addition, still following Okal and Bina (1994), three earthquakes (evid 913090, 907752, 899527) in the Supplementary Catalogue that were originally shallow (at 35 or 15 km depth) are now deep or intermediate-depth events;
    • evid = 906896 moved ~50 km SE and depth changed from 35 to 20 km;
    • evid = 906183 moved ~65 SW and depth changed from 15 to 35 km. The new location better fits the available stations data (e.g., the secondary azimuthal gap improved from 180.4° to 95.8° and number of defining stations from 66 to 93) and is in line with the results discussed by Eissler and McNally (1984) and Okal and Borrero (2011);
    • evid = 904745 (1934 Bihar earthquake) has been relocated ~50 km NE following the observations in Dunn et al. (1939) that suggests the occurrence of a smaller subevent preceding the mainshock of about 11 seconds, which caused some stations to pick the first subevent instead of the mainshock. We thank Roger Bilham (University of Colorado, USA) to bring this issue to our attention;
    • evid 904392, 901447, 895531, 882341 have depths updated from shallow (between 10 and 40 km) to intermediate depths (between 90 and 130 km). These four events all occurred in Romania and are listed in the Supplementary catalogue (only evid = 901447 was listed in the main catalogue). These updates are in line with the results shown in Constantinescu and Enescu (1964).
    • evid = 903029 moved ~13 km SW in line with results discussed in Okal (1999);
    • evid = 902352 has an updated depth of 60 km instead of 25 in line with the moment tensor solution of Okal and Reymond (2003);
    • evid = 902275 has an update depth of 150 km instead of 35 in line with Okal (1992);
    • evid = 900505 moved ~95 NE in line with the results of Doser (1990);
    • depth changes from 35 km to 10 km for evid 898384, 897530, 907095, 788372, 717700, 693569; depth change from 35 to 25 km for evid 575847. All these earthquakes are off-shore the west coast of Mexico;
    • evid = 895348 (1950 Mondy earthquake) has depth of 15 instead of 35 km in line with the results of Delouis et al. (2002);
    • evid = 887959 and 887963 moved ~17 km SE and ~35 km NE, respectively, and added for both a direct M0 from Doser (1992a);
    • evid = 878424 (1960 Agadir earthquake) moved ~11 km NE and now is located on land to better fit the findings summarized by Meghraoui et al. (1998) and references therein. We also updated the Mw proxy to 5.91 based on MS from 24 stations instead of 5.84 based on MS from 3 stations;
    • depth change from 50 km to 40 km for evid = 875869; depth change from 45 km to 35 km with epicentre moving ~30 km inland for evid = 848355. Such changes are made in line with the results discussed by Tichelaar and Ruff (1991);
    • depth change from 35 km to 53.1 km for evid = 769592; depth change from 37.3 km to 60 km for evid = 761389; depth change from 35 km to 60 km for evid = 877305; depth change from 30 km to 15 km for evid = 746346. Such changes are made in line with the results discussed by McCaffrey (1988);
    • depth changes following Kao and Peng (1991): depth = 25 km instead of 50 km for evid = 748383 and 36.4 km instead of 20 km for evid = 712852;
    • evid = 904192 has an update depth of 100 km instead of 15 in line with Russo et al. (1992) and Doser and Vandusen (1996). The event is still listed in the Supplementary Catalogue;
    • evid = 888446 has an update depth of 100 km in line with the results of, e.g., Brüstle et al. (2014) and Kkallas et al. (2018). The event is still listed in the Supplementary Catalogue;

  • Updated magnitude for the following earthquakes:

    • evid = 852478 has a proxy Mw of 5.6 instead of a direct Mw =5.9 that was wrongly assigned to the event;
    • evid = 819518 has a direct Mw = 6.32 instead of 6.5 due to a typo in the seismic moment originally inserted from Chinn and Isacks (1983);
    • evid 514717, 510553, 508442 have Mw proxy based on mb instead of MS as a result of the review done in the Rebuild project. These events occurred in 1985 and remain in the main catalogue with magnitudes ~0.6-0.8 units smaller;
    • evid = 7453151 (great Sumatra earthquake of 2004-12-26) has an updated GCMT Mw = 9.3 according to Tsai et al. (2005) instead of the standard GCMT solution. M0 has also been updated accordingly;

  • Added M0 from the literature for the following earthquakes:

    • from Dineva et al. (2002), evid = 16957813 (Kresna 1904 earthquake) and its large foreshock (evid = 610326271) have direct Mw = 7.0 and 6.8, respectively, resulting in the events being now listed in the main catalogue. The locations of the foreshock and mainshock have also been updated about 28 km and 38 South, respectvely;
    • from Caciagli et al. (2019), evid = 913466 has a direct Mw = 5.72. Location also updated ~11 km SSW.
    • from Stich et al. (2018), evid = 911442 has a direct Mw = 5.4. Depth also updated from 15 to 10 km;
    • from Susagna et al. (1994), evid = 911743 has a direct Mw = 5.3 and it is now listed in the main catalogue. Depth also updated to 10 km and location moved 47 km NNW;
    • from Batlló et al. (2010), evid = 907482 has a direct Mw = 5.1 and location moved about 13 km NNE;
    • from Okal (2019), evid = 900863 has an updated direct Mw = 7.96 instead of Mw = 7.6 from Kanamori (1977);
    • from Wiens (1985), evid 899313 and 887294 have direct Mw = 7.36 and 6.03, respectively;
    • from Batlló et al. (2008), evid = 894167 and 894355 have direct Mw = 5.2 and 5.3, respectively, resulting in evid = 894167 being now listed in the main catalogue. The locations have also been updated (about 37 km NE for evid = 894167 and 15 km NE for evid = 894355);
    • from Okal (1992), evid = 865885 has a direct Mw = 7.16 and it is now listed in the main catalogue;
    • from Alasset (2007) and Cara et al. (2008) , evid = 832236 has a direct Mw = 5.1;
    • from Okal et al. (2016), evid = 905646 has a direct Mw = 7.25.

20 June, 2018: Version 5.1 released

  • Added 17 earthquakes between 1933 and 1949, all but one from the Gutenberg and Richter catalogue; these events are undetermined shocks in the ISS and with station data not in tabulated form; to relocate and reassess the magnitude of these events we digitized and integrated parametric station data from the ISS, Gutenberg notepads, individual station bulletins and BCIS; twelve of these earthquakes (evid 16963127, 16963144, 16963678, 16964661, 16964943, 16965068, 16965286, 16965324, 16966074, 16966380, 16966502, 16967106) are listed in the Main catalogue and are all shallow in the magnitude range 6.0 to 6.4 (many occurring in mid-oceanic ridges); the remaining five earthquakes have poor location and/or magnitude and are listed in the Supplementary catalogue (evid 16963156, 16964624, 16965441, 16965882, 16965899);
  • The direct Mw and M0 for evid = 16957859 and 16957865 (Tsetserleg and Bolnay 1905 great earthquakes in Mongolia, respectively) sourced from Schlupp and Cisternas (2007) are now correctly associated (in V4 the Mw and M0 values were swapped). Thus the Tsetserleg (evid = 16957859) and Bolnay (evid = 16957865) earthquakes have Mw= 7.95±0.2 and earthquake 8.33±0.2, respectively. Also the seismic moment values have been updated accordingly. We thank Nobuo Hamada (formerly JMA) for pointing out the error;
  • Improved location and magnitude for the 1905-11-08 earthquake (Aegean Sea, Greece, evid = 16957878). The epicentre moved about 122 km N-NE (near Mt Athos peninsula) from previous location, whereas the proxy Mw = 7.24 is now based on MS from five stations (instead of two in previous catalogue versions). The small uncertainty of the updated magnitude allowed us to move the event from the Supplementary to the Main Catalogue;
  • Update location (about 270 km to the E) for evid 911802; also the magnitude has been improved since the Mw proxy is now based on MS from eight stations instead of five;
  • Evid = 909805 is now listed in the Supplementary Catalogue as its location quality flag has been update to D; we thank Paolo Harabaglia from the University of Basilicata (Italy) for pointing out the large error ellipse semi-major axis for this event;
  • Evid = 899720 now has a proxy Mw = 6.3 based on our re-computed MS after adding surface wave amplitudes from station HYD, India (MS from two stations, SVE and TIF, was not accepted in previous versions); the event is now listed in the Main Catalogue;
  • Updated the seismic moment M0 from the bibliographic search for evid = 828259 and 761994. In both cases the seismic moments from Richardson and Solomon (1977) were inserted with typos (1.12E+19 and 6.6E+18 Nm instead of 8.2E+18 and 6.4E+18 Nm for evid 828259 and 761194, respectively). Also the source reference for the seismic moment for evid = 828259 is now Singh et al. (1975) instead of Richardson and Solomon (1977). For both earthquakes the small variations in M0 does not significantly change the moment magnitude Mw (for evid = 828259 Mw changes from 6.6 to 6.54);
  • Replaced the Mw=6.5+/-0.2 from the bibliographic search for evid = 713088 with a proxy Mw=6.09+/-0.24 based on our re-computed mb;
  • Minor changes due to the review done in the Rebuild project (Storchak et al., 2017):
    • For close events 684685 and 684686 we have moved the GCMT solution from 684685 to 684686; evid = 684685 is now listed in the Supplementary Catalogue as its Mw proxy based on our re-computed mb has high uncertainty;
    • replaced evid = 805431 (event previously in the Supplementary Catalogue) with evid = 805429 (listed in the Main Catalogue);
    • replaced evid = 856064 with evid = 856063.

27 February, 2018: Version 5.0 released

Version 5.0 of the ISC-GEM Catalogue is the result of the 4th year of the Extension Project that began in November 2014. We included earthquakes smaller than 7.5 during 1904-1919 from a multitude of sources that were not processed in the past. We also included earthquakes that occurred in 2014. For earthquakes during 1904-1919 we had to digitize a multitude of station data sources from the ISA BAAS, ISS etc. and amplitude-period data added from original station bulletins to re-assess the magnitudes (mostly MS). The procedures used to digitize the parametric data is described in Di Giacomo et al. (2015). We did not add any station data before 1904 (basically only stations belonging to the Milne network are available, see, e.g., Adams, 1989) and, consequently, we decided to drop from the ISC-GEM catalogue the ten pre‑1904 events listed before Version 5 and have the catalogue starting in 1904.
Version 5.0 adds 521 earthquakes that occurred in 2014 with magnitude 5.5 and above and 1,110 for the period 1904-1919. For the latter period details of the extension are described in Di Giacomo et al. (2018).
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 to improve the re‑computed MS and, as a result, the Mw proxy. With the data newly available, we better constrained the MS for 146 earthquakes between 1904 and 1919 listed in previous versions by using more station magnitudes (e.g., 80% of the original MS was obtained from NSTA ≤ 10, for the updated MS this percentage drops to ~40%). Finally, we revised the hypocentre locations and/or magnitude of 7 earthquakes outside the period 1904-1919. Here we list in detail the changes affecting these events:

  • Evid = 16958009 has now a direct Mw = 7.1 following the paper by Pino et al. (2000);
  • Evid = 16958130, also known as the 1911 Kemin earthquake has an updated direct Mw = 8.0 following the recent paper of Kulikova and Krüger (2015). Also, the location has been updated after adding several phase readings;
  • Evid = 912062: updated location (~125 km to the SW) after considering the effects of the earthquake outlined in Ruiz and Madariaga (2018);
  • Evid = 908523: update location (~40 toward NNW and depth changed from 15 to 65 km) after Paolo Harabaglia (University of Basilicata, Italy) pointed out the need of improving the hypocentre;
  • Evid = 907513, also known as the 1930 Irpinia earthquake has now a direct Mw = 6.64 following the paper of Pino et al. (2008);
  • Evid = 902493 has an updated location which fits better the tsunami generation; we thank Jonathan Griffin from Geoscience Australia for his enquire on the location of this event and following discussions;
  • Evid = 722344, also known as the 1975 Hilo, Hawaii, earthquake has an updated direct Mw = 7.7 following the more recent paper of Nettles and Ekström (2004) instead of Kawakatsu (1989);
  • Deleted event 650848 as part of the review done in the Rebuild project (Storchack et al., 2017);

We thank Paolo Harabaglia from the University of Basilicata (Italy) for pointing out the direct Mw in the papers for the two significant earthquakes in Italy and the 29 November 1975 Hilo (Hawaii) earthquake.

26 January, 2017: Version 4.0 released

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 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. Here we list in detail the changes affecting these events:

  • Evid = 16957859 and 16957865 (known also as Bolnai and Tsetserleg 1905 great earthquakes in Mongolia, respectively) have an updated direct Mw following the more recent paper by Schlupp and Cisternas (2007) instead of the Okal (1992) paper. Whilst Mw for evid = 16957859 changed only slightly from 8.3±0.4 to 8.33±0.2, Mw for evid = 16957865 changed from 8.3±0.4 to 7.95±0.2. The seismic moment values have been also updated accordingly;
  • Banished event 805429 in the Supplementary Catalogue as it has been merged with evid = 805430;
  • Magnitude re-assessed for close events 855990 and 855991. We kept the MS for evid = 855990 and dropped MS for evid 855991, which is now listed in the Supplementary Catalogue;
  • Banished event 809906 as it has been merged to close event 809905;
  • Magnitude re-assessed for close events 759121 and 759122. The new Mw=5.64±0.32 proxy for evid = 759121 is based on mb=5.53±0.17, whereas for evid = 759122 Mw=6.45±0.20 is still based on MS;
  • Magnitude re-assessed for close events 759377 and 759378. The new Mw=5.62±0.54 proxy for evid = 759377 is based on mb=5.51±0.29, whereas for evid = 759377 Mw=6.15±0.20 is still based on MS;
  • Magnitude re-assessed for close events 756556 and 756557. Readings contributing to MS for those two events have been re-associated and whilst the MW proxy is based on MS for both events, the new Mw proxy for evid = 756556 is highly uncertain (5.95±0.81) and mover evid = 756556 in the Supplementary catalogue, whereas the new Mw proxy for evid = 756557 is 5.90±0.20;
  • Depth revision for three events in 2000: for evid 2348963 new depths is 55 km (previous was 36 km) whereas for evid 1912754 and 1741138 new depths is 100 km (previous depths were 25 and 85 km , respectively). The only change in magnitude is for evid = 1912754 where the Mw proxy is based on mb instead of MS and is highly uncertain (5.61 0.89). Thus evid = 1912754 is now listed in the Supplementary Catalogue.

28 January, 2016: Version 3.0 released

Version 3.0 of the ISC-GEM Catalogue is the result of the 2nd year of the Extension Project that began in November 2014. We included earthquakes smaller than 6.25 during 1935-1949 listed in the ISS but not processed in the past. We also included earthquakes that occurred in 2012. The recent data were available from the ISC Bulletin in an electronic format, but the arrival time data for earthquakes during 1935-1949 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 3.0 includes 414 earthquakes that occurred in 2012. For the period 1935-1949, we have relocated 4403 earthquakes and obtained new MS values for 2719 of them (available in the Main Catalogue). The events for which we could not re-compute the magnitude are listed in the Supplementary Catalogue

During the year we also received station bulletins kindly provided by the personal collection of Prof. N. Ambraseys, British Geological Survey (BGS) collection, bulletins from the Geophysical Institute of the Czech Academy of Sciences in Prague, the Geophysical Survey of the Russian Academy of Science in Obninsk and the EOST of the University of Strasbourg (France). Those station bulletins helped to fill some significant gaps in the ISC original collection and allowed to add new surface wave amplitude-period data for earthquakes listed in previous versions of the ISC-GEM Catalogue. With the data newly available, we better constrained the MS for 648 earthquakes between 1935 and 1949 listed in previous versions by using more station magnitudes (e.g., 42% of the original MS was obtained from NSTA ≤ 5, for the updated MS this percentage drops to ~5%). Finally, we revised the hypocentre locations of 92 earthquakes outside the period 1935-1949. Most of the revisions concerns depth amendments from the first step (EHB location) of the two-tier location approach before the epicentre is relocated with the ISC locator (see Bondár et al., 2015). These 92 earthquakes have occurred between 1905 and 2004 but mostly before 1979; 34 of them were listed in the Supplementary Catalogue.

10 July, 2015: Version 2.01 released

Removed evid = 877612 from the main catalogue as the event is a documented nuclear explosion in Novaya Zemlya.

19 January, 2015: Version 2.0 released

Version 2.0 of the ISC-GEM Catalogue is the result of the 1st year of the Extension project that began in November 2013. We included earthquakes smaller than 6.25 from the 1950s, listed in the ISS but not processed by us in the past. We also included earthquakes that occurred in 2010 and 2011. The recent data were available from the ISC Bulletin in an electronic format, but the arrival time data for earthquakes in the 1950’s had to be digitized from the ISS and amplitude-period data added in order to re-assess the magnitudes (mostly MS), using procedures described in Di Giacomo et al. (2015).

Version 2.00, therefore, now includes data for 504 earthquakes from 2010 and 672 from 2011. For the 1950s, we processed and relocated 4156 earthquakes and obtained 2216 new MS and 12 mb values. We also introduced a new magnitude quality flag “D” for the Mw proxies with uncertainty larger than 0.7, which is now listed in the Supplementary Catalogue. In addition, since many ISS earthquakes during the 1950s when processed resulted in MS smaller than 5 (i.e, much smaller than our catalogue cut-off magnitude of 5.5), we have listed them in the Supplementary Catalogue rather than excluding them completely from the Catalogue, with particular regard to the importance of re-assessing the magnitude of earthquakes before the beginning of the digital era.

During the year we also received station bulletins kindly provided by colleagues from Edinburgh, Eskdalemuir, Obninsk, Prague and Apatity. Those station bulletins helped us to fill some significant gaps in the ISCs original collection and allowed us to add new amplitude-period data for earthquakes listed in previous versions of the ISC-GEM Catalogue. With the data newly available, we obtained fresh magnitudes for about 200 earthquakes that were previously listed in the Supplementary Catalogue (Version 1.05) and added 237 new earthquakes between 1960 and 1963. Finally, we revised the hypocentre locations of 458 earthquakes in the catalogue, predominantly in remote areas, with 75% of depth changes within 20km and the rest within 60km.

14 February, 2014: Version 1.05 released

Updates to the catalogue regard 1) updated location and magnitude of the earthquake in Sumatra that occurred the 6 June 1943 (evid = 899872), which moved from the Supplementary Catalogue to the Main Catalogue; 2) updated the proxy MW for six earthquakes; 3a) addition of an earthquake (evid = 603952288) in the Main Catalogue that occurred in Turkey the 4 December 1905 and 3b) updated location of one of its aftershocks (evid = 16957879) that occurred approximately five hours later.

Details follow:

1) The location of the 6 June 1943 Sumatra earthquake has been updated and the epicentre moved to the North 40 km but most importantly the depth changed from 90 to a fixed depth of 10 km. Although the reported depth phase arrival times suggest that the hypocentre is around 90 km, we accept the 10 km depth since surface ruptures were reported (see, e.g., Untung et al., BSSA 1985). Hence, the event now moved from the Supplementary Catalogue to the Main Catalogue as with the shallow depth solution MS is available. From 12 stations we obtain MS= 7.8 +/- 0.1, which lead to a MW proxy of 7.81 +/- 0.25. We thank James Dewey (USGS Emeritus) for drawing our attention to this event.

2) the proxy MW for six earthquakes (evid 679878, 1656088, 1656090, 1728632, 13389548, 11911358) has been updated. With the exception of evid = 679878, the proxy MW is now based on mb instead of MS. The MS for those earthquakes was based on few stations with suspiciously large amplitudes. For evid = 679878 we obtained a new MS after correcting the surface wave amplitude units at six stations from micrometers to nanometers. The new six MW proxies are significantly smaller than the previous ones.

3a) the mainshock of the East Anatolian Fault sequence that occurred the 4 December 1905 has been added (evid = 603952288) after collecting arrival times from the ISA bulletin (61 arrivals) and surface wave amplitudes from four stations (GTT, LEI, POT, JEN). The event was missing due to a mis-association in the Centennial Catalogue between magnitude and origin time of the mainshock with one of its aftershocks;
3b) the location of the aftershock at 12h (evid = 16957879), which was already available in previous releases, has been updated. The previous ISC-GEM location was close to Aleppo, Syria, whereas the current location is much closer to the East Anatolian Fault.

5 November, 2013: Version 1.04 released

We noticed that the Appendix is not recognised by our users as an important part of the ISC-GEM Catalogue. We therefore renamed the Appendix to be called Supplementary Catalogue.

The terms of the license have also changed to reflect the availability of the ISC-GEM Catalogue to all parties.

Updates to the catalogue regard 1) the proxy Mw for the 12 April, 1967 earthquake in the Leeward Islands region (evid = 836598) and 2) the GCMT solution for the complex event occurred near Potenza (South Italy) the 1990-05-05 (evid = 368231). With regard to the Leeward Islands 1967 event the original proxy Mw = 7.4 was based on the MS from three mis-associated station amplitude readings. The updated proxy Mw 5.0 is based on mb. We thank Uri Ten Brink from USGS office in Woods Hole, MA, for pointing out the excessive magnitude value. With regard to the complex Potenza earthquake of 1990-05-05, the GCMT solution has been moved to evid = 368231 from evid = 368230. These two events are separated by approximately 10 seconds and are interpreted as foreshock (evid = 368230) and mainshock (evid = 368231). For more details see, e.g., Ekström (1994). Since the magnitude estimates for the foreshock are uncertain, evid = 368230 is now listed in the Supplementary Catalogue. We thank Paolo Harabaglia (University of Basilicata, Potenza, Italy) for drawing our attention to these events and Göran Ekström (Lamont-Doherty Earth Observatory of Columbia University, USA) for discussing the association of the GCMT solution.

11 June, 2013: Version 1.03 released

Updated the location for the earthquake occurred near coast of Venezuela the 1929-01-17 (evid = 907860) and the Mw for the 1967-07-30 Caracas earthquake (evid = 833882). The new location for the 1929-01-17 earthquake is about 98 km north the previous one and fits better with the tsunami observation for this event. The Mw = 7.0 for the 1967-07-30 Caracas earthquake initially adopted from Rial (JGR, 1978) has been replaced with a more recent determination of M w = 6.6 by Suárez and Nábělek (JGR, 1990). We thank Michael Schmitz and Herbert Rendon from the Applied Geophysics Department, Fundación Venezolana de Investigaciones Sismológicas (FUNVISIS), for inquiring about the location and magnitude of these earthquakes.

1 May, 2013: Version 1.02 released

Updated are the Mw proxy values for 84 earthquakes between 1988 and 2009. The Mw proxies were based on excessively large MS based on the surface wave amplitudes reported by just a few stations or a single agency. The updated Mw proxies are now based on mb. In particular, we thank Helene Lyon-Caen and colleagues from the Laboratoire de Géologie, Ecole Normale Supérieure in Paris, for pointing out the large Mw proxies for two earthquakes in Greece.

26 Feb, 2013: Version 1.01 released

Updated the Mw and Mw proxy values of eight large earthquakes (evids 906508, 897799, 895348, 863756, 830410, 825732, 795586, 736783) following an additional review of corresponding scientific articles and correcting typographic errors in the results of the original bibliographical search for reliable seismic moments. In particular, we thank
Dr. Alexey Ivashchenko from the Tsunami Lab of the Institute of Oceanology, Russian Academy of Sciences, Moscow for pointing out an erroneous Mw for the Mondy earthquake (Baikal rift zone) of April 4, 1950 (evid = 895348).

31 Jan, 2013: Version 1 released

This was the first public release of the Catalogue following the completion of the 27 months project.