Publication Date:
2017-04-05
Description:
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.
Electronic ISSN:
2195-9269
Topics:
Geography
,
Geosciences
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