Vertical seismic ground shaking in the volcanic areas of Italy: prediction equations and PSHA examples

This work introduces a new Ground Motion Model (GMM) to predict the horizontal and vertical components of PGA, PGV and acceleration response spectra up to 5s for the volcanic events in Italy. The model updates the GMM for the horizontal components, recently developed by Lanzano & Luzi [1], and shows relevant amplitudes in near-source and a frequency content richer in intermediate-to-low frequencies. The comparison with an event not used for the calibration and belonging to another volcanic district in Italy is promising for the extension of the model to other areas. Finally, we present a case study of a site, in the proximity of Mount Etna in eastern Sicily region, which allows us to evaluate the impact of these models in the framework of a Probabilistic Seismic Hazard Analysis (PSHA). •a ground motion model for the vertical component of volcanic earthquakes in Italy is proposed.•The ground motion can be high in near-source conditions for shallower events.•The shallow volcanic events attenuates with distance rapidly than the active crustal ones.•The peak frequency content of volcanic events is shifted to lower frequencies.•a PSHA case study is discussed with focus on the impact of the use of the GMM proposed in the paper.