GNGTS 2014 - Atti del 33° Convegno Nazionale

The key parameter for any EEWS is the “lead-time”, which is the time available for protecting measures at distant targets once an earthquake has been promptly detected and characterized, and an alarm is issued. The lead-time for regional EEWS is defined as the travel-time difference between the P-waves recorded in the source area and the arrival of first S-waves at the target site, after accounting for the necessary computation and data transmission times. In on-site EEWS the lead-time is equal to the difference in P- and S-wave arrival times at the target itself. Recently Zollo et al. (2010) demonstrated that the two approaches can be profitably integrated within an integrated system that allows the early estimation of the Potential Damage Zone (PDZ) associated to an event. Clearly, the integration of regional and on-site approaches results particularly useful whenever target sites are threatened by more than one seismic source areas, and these latter are placed at variable distances from the target sites. An exhaustive review of the concepts, methods, and physical basis of EEWS has been presented by Satriano et al. (2010). PRESTo continually processes real-time streams of three-component acceleration data detecting P-waves arrival, and following the idea proposed by Zollo et al. (2010) implements both regional and on-site approaches. Alarm messages containing the evolutionary estimates of source and ground motion at target parameters, with associated uncertainties, are sent via internet and can thus reach also distant vulnerable infrastructures before the destructive waves, enabling the initiation of automatic safety procedures. Since 2009 PRESTo is under real-time experimentation in Southern Italy on the data streams of the Irpinia Seismic Network (ISNet). Real-time testing is also underway in South Korea on the KIGAM network (Korean Institute of Geoscience and Mineral Resources), in Romania on RoNet - Romanian Seismic Network (National Institute of Research and Development for Earth Physics), and in the Marmara region (Turkey) on the KOERI network (Kandilli Fig. 1 – The PRESTo stations. GNGTS 2014 S essione 2.3 465