International Seismological Centre (ISC)

The International Seismological Centre (ISC) was set up in 1964 with the assistance of UNESCO as a successor to the International Seismological Summary (ISS) to follow up the pioneering work of Prof. John Milne and Sir Harold Jeffreys in collecting, archiving and processing seismic station and network bulletins and preparing and distributing the definitive summary of world seismicity.

Under the umbrella of the IASPEI, the ISC always played an important role in setting up international standards such as the International Seismic bulletin Format (ISF), the IASPEI Standard Seismic Phase List and the IASPEI Manual of the Seismological Observatory Practice.

The ISC was always serving the scientific research and the most prominent scientists such as John Hodgson, Eugine Herrin, Hal Thirlaway, Jack Oliver, Anton Hales, Ola Dahlman, Shigeji Suehiro, Nadia Kondorskaya, Vit Karnik, Stephan Muller, David Denham, Adam Dziewonski, John Woodhouse and Guy Masters considered it an important duty to serve on the ISC Executive Committee and the Governing Council.

The current mission of the ISC is to maintain:

the ISC Bulletin – the longest continuous definitive summary of World seismicity (jointly with ~130 seismic networks and data centres around the world); the International Seismographic Station Registry (IR, jointly with NEIC/USGS); the IASPEI Reference Event List (Ground Truth, GT, jointly with IASPEI). These are fundamentally important tasks. Bulletin data produced, archived and distributed by the ISC for almost 50 years is the definitive source of such information and are used by thousands of seismologists worldwide for seismic hazard estimation, for tectonic studies and for regional and global imaging of the Earth’s structure. Key information in global tomographic imaging is derived from the analysis of ISC data. The ISC Bulletin served as a major source of data for such well known products as the ak135 global 1-D velocity model and the EHB and Centennial catalogues. It presents an important quality-control benchmark for CTBTO. ISC Bulletin data are used by the IRIS DMC to serve event oriented user requests for waveform data. The ISC Bulletin is a corner stone of the Global Reference Catalogue for Global Earthquake Risk Model (GEM).

The ISC relational database currently holds approximately 90 GB of unique data. The ISC Bulletin contains over 4 million seismic events: earthquakes, chemical and nuclear explosions, mine blasts and mining induced events. As many as 1.5 million of them are moderate to large events that have been reviewed by the ISC analysts. The Bulletin contains approximately 50 million individual seismic station readings of arrival times, amplitudes, periods, SNR, slowness and azimuth, reported by approximately 17,000 seismic stations currently registered in the IR. As many as 6,000 stations have contributed to the ISC Bulletin in recent years. This number includes the numerous sites of the USArray. The IASPEI GT List currently contains 7410 events for which latitude, longitude and depth of origin are known with high confidence (to 10 km or better) and seismic signals were recorded at regional and/or teleseismic distances.