GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 2.1 GNGTS 2024 The Multi Synthetic Catalog Analysis (MSCA) as a tool to evaluate seismic hazard, risk and resilience T. Tufaro 1 1 School of Civil Engineering, University of Basilicata, I-85100 Potenza, Basilicata, Italy The classical approach to seismic hazard evaluation is the PSHA method (Cornell, 1968). It is still an excellent approach if we are interested in computing seismic hazard only. However if we wish to include other quantities such as risk or resilience it is better to follow a different method. The proposal presented here is based on the concept of building a very large number of synthetic catalogs (up to several hundred thousands) that will result in tens of millions of events. It naturally allows for inclusion of: Risk and resilience scenarios probability ; Time evolution . The acceleration is computed at each site and the damage is evaluated: each event generates a complete probabilistic scenario. Let us suppose focusing on bridges; a damage scenario where fragility curves can be considered also probabilistic, will lead to the possibility of computing the total repairing cost and necessary timing. This in turn will allow for evaluating the disturbance to local communities, the interruption of local traffic and the overall time necessary to recover it. All of the aboves can be evaluated with a probabilistic setting. The statistics are then conducted on all scenarios. The underlying idea is that, set the quantity we are looking for, let us say the numbers of days commuters loose because of road interruption, and set the number of synthetic catalogs, let us say 100.000, we will select the 100.000 largest values (out of even tenths of millions of events) where the 10% probability threshold will be the one at the 90.000 largest value. Every scenario has a centroid, so the process can be repeated for every possible centroid location. It is obviously a very computationally heavy approach but it can give the appropriate view where major issues are expected. Moreover it is possible to introduce a full time dependent seismic evaluation of the hazard. Fig.1 shows the hazard due the classical seismic zoning (attenuation: Bindi et al., 2011). Since the attenuation law is different from those used in the MPS04, it looks obviously slightly different but it conveys the idea of the equivalence of the two approaches.