GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 2.1 303 Nevertheless, this approach uses as much as possible the information from known faults which, depending on the level of knowledge and on the local tectonic complexity, among other things, can be modelled in three different ways: 1) Predominant Seismicity (PS), 2) Background Seismicity (BS), Special Background Seismicity (SBS). PS is used when it is possible to assume the fault geometry and mechanism to be sufficiently known (e.g. for the main subduction zones) and future earthquakes are predicted to occur only on those fault surfaces. The BS is used for modelling the seismicity around the PS faults and in all cases where future earthquakes can be assumed to occur anywhere in a volume, similarly to typical seismic hazard approaches. In this latter approach, the potential sources are distributed on a regular lattice where the information on faults is merged with that on past seismicity, dominant stress regime, and tectonic characterization, to determine a probability density function for the faulting mechanism. The SBS is a special category used when major structures are thought to be present but their geometry and position is not well-enough constrained. To illustrate the methodology and its impact on the hazard estimates, we present the results of an application for estimating the tsunami impact along the coastlines of the NE Atlantic, the Mediterranean, and connected Seas (NEAM) region. For the deterministic numerical modeling of tsunamis we use the database of pre-calculated tsunami scenarios of elementary sources (Molinari et al. , 2016) constructed with numerical simulations performed with Tsunami-HySEA (Macías et al. , 2017). The impact of tsunamis on Fig. 1 - Disaggregation per cell for intensity ψ> 1 m; this map is a spatial distribution of the causative source probability for a tsunami at the site which exceeds the selected threshold. Red crosses indicate the location of the target in each panel (Selva et al. , 2016).