The Centre maintains a continually growing file of past earthquakes, which is available for research studies and to help with the assessment of seismic hazard. This file contains estimates of origins of earthquakes dating from 1904 but naturally only major earthquakes are present for the earlier years. The file becomes more complete with time and now contains more than 1,000,000 events world-wide. About 150,000 more events are added each year.
The main sources of data for the Historical Earthquake File are the International Seismological Summary for the period 1913-63 and the ISC thereafter. Additional sources include the Bureau Central International de Séismologie, Strasbourg, the US Coast and Geodetic Survey and standard catalogues such as "Seismicity of the Earth" by Gutenberg and Richter. For the period more recent than that for which ISC information is available, information from the Preliminary Determination of Epicenters, and Quick Epicenter Determination Services of the US National Earthquake Information Center is added to the file, and preliminary telexed information about major events is included within a few weeks of occurrence. The file contains details of earthquakes from the instrumental period only, with no events before 1904.
Events can be selected from the file by any combination of criteria, relating to time, location, depth, magnitude, intensity or locating agency. Composite estimates can also be provided which combine origin parameters with magnitude determinations from other agencies.
The information can be provided on CD or diskette or by e-mail in a variety of formats. Epicentre maps can also be provide in PostScript format.