Seismic monitoring in Northeastern Italy: a ten-year experience

The Friuli Automatic Alert System (FAAS; Bragato andGovoni, 2000) is a rapid-location system developed in 1996to satisfy the requirements of the Civil Protection of Friuli-Venezia Giulia. FAAS runs on the same computer runningthe MARS88/RC acquisition system. It is composed of three modules (Analyzer, Decision Maker, and Communicator)implemented as independent processes that communicatethrough standard files. The Analyzer draws data from the signaldatabase and starts processing if a coincidence arisesamong at least four stations. It recognizes local earthquakesbased on the frequency content of the seismograms, performsP and S picking, locates the earthquakes, and estimates theirmagnitudes. The results of the analysis are sent to the DecisionMaker, which establishes the level of alert and the usersto notify (in particular, authorities responsible for emergencymanagement and seismological institutions). The Communicatorproduces the appropriate messages and sends them byfax, e-mail, or short messages on the cellular phone. Automaticlocations are also reported on the CRS Web page(http://www.crs.inogs.it/) and on a monitor located in theemergency room of the Civil Protection of Friuli-VeneziaGiulia. During the night and off-duty days, the system alsoalerts a seismologist by cellular phone. If necessary, the seismologistcan reach CRS in about half an hour to verify theearthquake's location, follow any seismic sequence, and supportdecisions by Civil Protection authorities. For regional orteleseismic earthquakes, FAAS e-mails other seismologicalinstitutions with messages containing P arrival times. Due tothe transmission modalities described before, FAAS has aresponse time (from the origin time of the earthquake to theproduction of the first location) of about 7 minutes.