Ground-motion predictive equations for low-magnitude earthquakes in the Campania–Lucania area, Southern Italy

Abstract

A key aspect of ground-shaking map calculation is represented by ground-motion predictive equations (GMPEs). In fact, ground-shaking maps obtained soon after an earthquake are calculated by integrating observed data and ground-motion estimates from GMPEs for those areas not covered by seismic stations. Empirical ground-motion models that are used to obtain these estimates refer primarily to strong ground-motion due to large earthquakes and cannot be properly used to estimate the effects of small magnitude seismic events. In this paper we calibrated GMPEs for low-magnitude earthquakes from data recorded at the seismographic stations of the Irpinia Seismic Network, in the Campania–Lucania region, Southern Italy. In particular, the available dataset is formed by peak ground acceleration (PGA) and velocity (PGV) parameters coming from 123 earthquakes (local magnitudes ranging between 1.5 and 3.2) recorded at 21 stations of the ISNet network at hypocentral distances from 3 km to about 100 km. The total number of peaks measurements is 875. This study is part of a research project, in collaboration with the Italian Department of Civil Protection and National Institute of Geophysics and Volcanology, aimed at producing ground-motion shaking maps.