11:30 AM - 11:45 AM
[S01-2-05] The ISC-GEM Global Instrumental Earthquake Catalogue: Current status and efforts to extend the period 1904-1919
The first version of the ISC-GEM Global Instrumental Earthquake Catalogue (1900-2009) (www.isc.ac.uk/iscgem/index.php) was released in January 2013 (Storchak et., 2013) after a 27-month project co-funded by the GEM Foundation. The catalogue was required to reassess the homogeneity (to the largest extent possible over time) of the earthquake parameters (especially location and magnitude) and list them along with formal uncertainties to facilitate seismic hazard and Earth's seismicity studies.
The first release included earthquakes selected according to the following time-variable cut-off magnitudes: Ms=7.5 before 1918; Ms=6.25 during 1918-1963; and Ms=5.5 from 1964 onwards. Because of the importance of having a reliable seismic input for seismic hazard studies, funding from USGS, NSF, GEM and a few commercial companies in the US, UK and Japan allowed us to start working on the extension of the ISC-GEM catalogue both for earthquakes that occurred after 2009 and historical earthquakes listed in the International Seismological Summary (ISS), which fell below the original ISC-GEM cut-off magnitude of 6.25 before 1964. This is a four-year project that aims to add as many earthquakes as possible that occurred between 1904 and 1959. In this contribution we present the updated ISC-GEM catalogue at the end of the third year extension program (Version 4.0), which includes over 2,000 more earthquakes during 2010-2013 and thousands more between 1920 and 1963 as compared to the first version. We also discuss the current work to include as many earthquakes as possible during 1904-1919. The extension of the ISC-GEM catalogue will be useful to regional seismic hazard studies because the ISC-GEM catalogue can serve as basis for cross-checking location and magnitude of those earthquakes listed both in global and regional catalogues.
The first release included earthquakes selected according to the following time-variable cut-off magnitudes: Ms=7.5 before 1918; Ms=6.25 during 1918-1963; and Ms=5.5 from 1964 onwards. Because of the importance of having a reliable seismic input for seismic hazard studies, funding from USGS, NSF, GEM and a few commercial companies in the US, UK and Japan allowed us to start working on the extension of the ISC-GEM catalogue both for earthquakes that occurred after 2009 and historical earthquakes listed in the International Seismological Summary (ISS), which fell below the original ISC-GEM cut-off magnitude of 6.25 before 1964. This is a four-year project that aims to add as many earthquakes as possible that occurred between 1904 and 1959. In this contribution we present the updated ISC-GEM catalogue at the end of the third year extension program (Version 4.0), which includes over 2,000 more earthquakes during 2010-2013 and thousands more between 1920 and 1963 as compared to the first version. We also discuss the current work to include as many earthquakes as possible during 1904-1919. The extension of the ISC-GEM catalogue will be useful to regional seismic hazard studies because the ISC-GEM catalogue can serve as basis for cross-checking location and magnitude of those earthquakes listed both in global and regional catalogues.