Reversible ground motion-to-intensity conversion equations based on the EMS-98 scale

The relation between observed macroseismic intensities and recorded ground motion parameters is a matter of interest in earthquake engineering, and it has been widely discussed in literature in the past. Several relationships already exist, correlating macroseismic intensity and peak ground motion parameters (i.e. PGA, PGV or PGD, respectively peak ground acceleration, velocity and displacement). However, most of these formulations are based on Mercalli-Cancani-Sieberg (MCS) scale, developed using regional databases and difficult to be applied at large scale. In this research, new formulations are proposed that correlate European Macroseismic Scale (EMS-98) with ground shaking parameters (PGMs), Arias intensity and Housner intensity. An initial PGM/EMS-98 intensity dataset was assembled for this scope, collecting 610 data pairs of observations, from 35 different Italian seismic events derived from the Parametric Catalogue of Italian Earthquakes (CPTI15) and the Italian Accelerometric Archive (ITACA), subsequently filtered considering only tectonic events and data pairs with site – station distances lower than 3 km. The resulting final dataset of 220 data pairs from 22 earthquakes was thus used to obtain regression relationships, finally compared with existing models based on the Modified Mercalli (MM) scale and MCS scale.