The ISC-GEM Earthquake Catalogue (1904–2014): status after the Extension Project

Abstract

Abstract. We outline the work done to extend and improve the ISC-GEM Global Instrumental Earthquake Catalogue, a dataset which was first released in 2013 (Storchak et al., 2013, 2015). In its first version (V1) the catalogue included global earthquakes selected according to time-dependent cut-off magnitudes: 7.5 and above between 1900 and 1918 (plus significant continental earthquakes 6.5 and above); 6.25 between 1918 and 1959; 5.5 between 1960 and 2009. Such selection criteria were dictated by time and resource limitations. With the Extension Project we added both pre-1960 events below the original cut-off magnitudes (if enough station data were available to perform relocation and magnitude recomputation) and added events with magnitude 5.5 and above from 2010 to 2014. The project ran over a 4-year period during which a new version of the ISC-GEM Catalogue was released each year via the ISC website (http://http://www.isc.ac.uk/iscgem/, last access: 10 October 2018). For each year, not only have we added new events to the catalogue for a given time range but also revised events already in V1 if additional data became available or location and/or magnitude reassessments were required. Here we recall the general background behind the production of the ISC-GEM Catalogue and describe the features of the different periods in which the catalogue has been extended. Compared to the 2013 release, we eliminated earthquakes during the first 4 years (1900–1903) of the catalogue (due to lack of reliable station data), added approximately 12 000 and 2500 earthquakes before 1960 and between 2010 and 2014, respectively, and improved the solution for approximately 2000 earthquakes already listed in previous versions. We expect the ISC-GEM Catalogue to continue to be one of the most useful datasets for studies of the Earth's global seismicity and an important benchmark for seismic hazard analyses, and, ultimately, an asset for the seismological community as well as other geoscience fields, education and outreach activities. The ISC-GEM Catalogue is freely available at https://doi.org/10.31905/D808B825.

Surface creep rate distribution along the Philippine fault, Leyte Island, and possible repeating of Mw ~ 6.5 earthquakes on an isolated locked patch

“…One of the focusing earthquakes in the present study, an M s 6.9 event in 1947 in northern Leyte, was overlooked in the catalog and hence by Besana and Ando (2005). This event is included in the catalogs of ISC-GEM (Di Giacomo et al 2018) and of the Philippine Institute of Volcanology and Seismology (PHIVOLCS 2018).…”

Geological and Geophysical Factors Constraining the Occurrence of Earthquake Precursors in Geofluids: A Review and Reinterpretation

“…Previous researches have evidenced that a significant part of the precursory signals was recorded in extensional areas (Cicerone et al, 2009;Martinelli and Dadomo, 2017; Supplementary Figure S2 in Supplementary Material). Recent data sets published by Lucazeau (2019), Di Giacomo et al (2018) and the International Seismological Center (2020) have allowed us to constrain further the geodynamic environment where the "occurrence of earthquake precursors" has a high probability. We assigned to each precursor of our catalog the spatially correspondent heat flow value (Lucazeau, 2019; see Supplementary Figure S1 in Supplementary Material), average hypocentral depth (within a search radius of 100 km) and distance from the nearest Holocene/Pleistocene volcano (Global Volcanism Program, 2013).…”

Evidence for Synchronization in the Global Earthquake Catalog

“…We use the 2018 ISC‐GEM release (Di Giacomo et al, 2018; Storchak et al, 2013). To test the completeness of the catalog, we plot the annual earthquake count for different magnitudes in 0.2 Mw increments on a log linear graph for the period 1905–2017 (Figure S1 in the supporting information).…”