Simulated shaking maps for the 1980 Irpinia earthquake, Ms 6.9: Insights on the observed damage distribution

The region stricken by the Irpinia earthquake (Ms=6.9) on 1980, along the Southern Appenninc chain, is one of the highest seismic hazard areas of Italian peninsula.This event produced vast damaging and strong amplitude shaking on a wide area. This is mostly related to the occurrence of a multiple fracture process during which three different segments of a sub-parallel normal fault system have been activated. The principal aim of this study is to investigate how the source complexity can have influenced the ground motion recorded at the earth surface and the areal distribution of strong motion parameters and observed building damage. We use a deterministic approach to simulate the ground motion scenario in the whole Campania region generated by the Irpinia event, based on the present knowledge of its rupture history and multiple faulting geometry. The kinematic source model has been calibrated by comparing the observed and synthetic data in frequency and time domain. Maps of the main strong motion parameters and damage maps for different class of buildings and levels of damage have been computed and quantitatively compared to the observations of damages and macroseismic intensity data.