Development of a site conditions map for the Campania-Lucania region (southern Apennines, Italy)

Abstract

Having a reliable site conditions estimate is an important step to analyze and predict earthquake ground motions. To provide this information for the Campania-Lucania region (southern Apennines, Italy), in the framework of a collaboration with regional civil protection agency, geologic units shown on 1:250,000 scale geologic map, have been sorted together into four categories based on age and geological similarities. According to the site classification defined in engineering building codes, we have assigned to each site classes, a value or range of values of the average shear-wave velocity to 30 m (Vs30) and of the site dominant period. Thus, we have digitized the category boundaries from the map tracing only the geologic contacts that separate units of different site classes. The accuracy of the site-conditions map is only limited by the number of Vs profiles, used to compute the Vs30, and geologic data available so far. Analyses with new data will allow updates and modifications of this map. Anyhow, the resulting site classification map may be an helpful tool to better characterizing the sites effects for those applications where amplification values at large scale are need, such as ground-shaking maps or seismic hazard maps.