GNGTS 2015 - Atti del 34° Convegno Nazionale

GNGTS 2015 S essione 2.1 the proper source-site distances, essential in our case. Similar new functionalities have then been implemented in O pen Q uake (by M. Pagani and R. Gee, Eucentre Pavia), the platform used by GEM (Global Earthquake Model) and SHARE Project. A synthetic example of the contribution of the Digital Elevation Model (DEM) to the hazard is shown in Fig. 1. The inclusion of a real topography influences the source-to-site distance, and thus the final results on PSHA: in the sensitivity tests performed with the Etna GMPEs, it causes a decrease of ground motion parameters that locally may reach about 20% of the expected values. Last but not the least, the site effects play an important role on seismic hazard, and in a new generation map amplification factors obtained by instrumental measurements should be taken into account. In the INGV-DPC V3 Project, the amplification coefficients have been calibrated in a densely urbanized area of the lower eastern flank (see Lombardo and Panzera, RU 6 in INGV-DPC V3 Project Final Report, 2015), and then introduced into the computational scheme performed by C risis . Fig. 3 – Seismic hazard maps obtained by using area sources with GR calibrated on instrumental and historical data (Branch 1), GMPE derived ad-hoc for the Etna region (Tusa and Langer, 2015) and amplification coefficients derived from site measurements (Lombardo and Panzera, RU 6 in INGV-DPC V3 Final Report, 2015). The computations have been done using CRISIS v.2015. Poisson model; exceedance probability, 10%; exposure times, 10 and 30 yrs; spectral acceleration at 1.0 s.