An Efficient Rapid Warning System For Earthquakes In The European-mediterranean Region

Every year a few damaging earthquakes occur in the European-Mediterranean region. It is therefore indispensable to operate a real-time warning system in order to pro- vide rapidly reliable estimates of the location, depth and magnitude of these seismic events. In order to provide this information in a timely manner both to the scientific community and to the European and national authorities dealing with natural hazards and relief organisation, the European-Mediterranean Seismological Centre (EMSC) has federated a network of seismic networks exchanging their data in quasi real-time. Today, thanks to the Internet, the EMSC receives real-time information about earth- quakes from about thirty seismological institutes. As soon as data reach the EMSC, they are displayed on the EMSC Web pages (www.emsc-csem.org). A seismic alert is generated for any potentially damaging earthquake in the European-Mediterranean re- gion, potentially damaging earthquakes being defined as seismic events of magnitude 5 or more. The warning system automatically issues a message to the duty seismolo- gist mobile phone and pager. The seismologist log in to the EMSC computers using a laptop PC and relocates the earthquake by processing together all information pro- vided by the networks. The new location and magnitude are then send, by fax, telex, and email, within one hour following the earthquake occurrence, to national and inter- national organisations whose activities are related to seismic risks, and to the EMSC members. The EMSC rapid warning system has been fully operational for more than 4 years. Its distributed architecture has proved to be an efficient and reliable way for the monitoring of potentially damaging earthquakes. Furthermore, if a major problem disrupts the operational system more than 30 minutes, the duty is taken, over either by the Instituto Geografico National in Spain or by the Istituto Nazionale di Geofisica in Italy. The EMSC operational centre, located at the premises of CEA / DASE in Bruyères le Châtel (France) operates 24 hours a day, 7 days a week. Although EMSC focuses on the European-Mediterranean region, the rest of the world is monitored, but for increasing magnitudes as the distance from this region increases. It generates between 70 to 100 warning messages each year. The utility of this EMSC service is clearly demonstrated by its following among the public : EMSC email dissemination list has been subscribed by about 200 institutions or individuals and there have been, for example, more than 800 connections to our Web site in the 48 hours following

1 the M5.8 earthquake of the Aegean Sea (27/07/2001, alert sent 47 minutes after its occurrence).

2