When probabilistic seismic hazard climbs volcanoes: the Mt Etna
case, Italy – Part 2: computational implementation and first results
Laura Peruzza1, Raffaele Azzaro2, Robin Gee1,5, Salvatore D'Amico2, Horst Langer2, Giuseppe Lombardo3, Bruno Pace4, Marco Pagani5, Francesco Panzera3, Mario Ordaz6, Miguel Leonardo Suarez6, and Giusy Tusa21Istituto Nazionale di Oceanografia e di Geofisica Sperimentale – OGS, Sgonico (TS), 34010, Italy 2Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione di Catania – Osservatorio Etneo, 95123, Italy 3University of Catania, Dep. of Biological, Geological and Environmental Science, Catania, 95129, Italy 4DiSPUTer, Università "G. d’Annunzio" Chieti-Pescara, 66013, Chieti, Italy 5GEM Foundation, Pavia, 27100, Italy 6UNAM, Coyoacan 04510, CDMX, Mexico
Received: 30 Mar 2017 – Accepted for review: 03 Apr 2017 – Discussion started: 05 Apr 2017
Abstract. This paper describes the model implementation and presents results of a probabilistic seismic hazard assessment (PSHA) for the Mt Etna volcanic region in Sicily, Italy considering local volcano-tectonic earthquakes. Working in a volcanic region presents new challenges not typically faced in more standard PSHA, which are most broadly due to the nature of the local volcano-tectonic earthquakes, the cone shape of the volcano, and the attenuation properties of seismic waves in the volcanic region. These have been accounted for through the development of a seismic source model that integrates data from different disciplines (historical and instrumental earthquake datasets, tectonic fault data, etc. presented in a companion paper Part I, Azzaro et al., 2017), and by the development and software implementation of original tools for the computation, such as a new ground-motion prediction equation and magnitude-scaling relationship specifically derived for this volcanic area, and the capability to account for the surficial topography in the hazard calculation, which influences source-to-site distances. Hazard calculations have been carried out using two widely used PSHA software packages (CRISIS, Ordaz et al., 2013; the OpenQuake-engine, Pagani et al., 2014). Results are referred to short to mid-term exposure times (10 % probability of exceedance in 5 and 30 years, Poisson and time-dependent) and spectral amplitudes of engineering interest. A preliminary exploration of the impact of site-specific response is also presented for the most densely inhabited region, and the variability in expected ground motion is finally commented. These results do not account for the M > 6 regional seismogenic sources that dominate the PSHA at long return periods, but present a different viewpoint that we believe is also relevant for retrofitting of the existing buildings, and for driving impending interventions of risk reduction.
Peruzza, L., Azzaro, R., Gee, R., D'Amico, S., Langer, H., Lombardo, G., Pace, B., Pagani, M., Panzera, F., Ordaz, M., Suarez, M. L., and Tusa, G.: When probabilistic seismic hazard climbs volcanoes: the Mt Etna
case, Italy – Part 2: computational implementation and first results, Nat. Hazards Earth Syst. Sci. Discuss., doi:10.5194/nhess-2017-121, in review, 2017.