The SED compiles the earthquake catalogue for Switzerland and surrounding regions, spanning historical events dating back to AD250 to events occurring only minutes ago. The quality and reliability of the information in the earthquake catalogue varies hugely depending of the date of the event.
Historical events are only roughly understood, information gathered from geological observations.
Up until to the mid 1970s, events can be located and magnitudes determined by analysing ‘macroseismic’ intensities derived from descriptions of the events in the literature, and more recently, by information from the epicentral region directly solicited by the SED.
Since 1975, the earthquake catalogue is instrumental - meaning it is completely determined using the seismic network infrastructure operated at the SED. As the network has become progressively more dense, with improved instrumentation (in particular more reliable timing) and improved computing resources, the earthquake locations and magnitudes have become more accurate, and the minimum magnitude threshold lowers.
The SED catalogue can be accessed through a variety of tools that are described below.