Mapping 1D seismic amplification effects in the range of periods of engineering interest based on geological data

Regional scale seismic hazard assessment including the effect of local seismo-stratigraphical conditions is a basic tool for seismic risk estimates. A novel physically based procedure is proposed for using geological maps to extensively estimate expected seismic amplification effects relative to spectral ordinates of main engineering interest (<0.8 s). Automatic GIS based analysis of geological maps, statistical data relative to the seismic/geotechnical properties of geological units and numerical modelling are combined to determine the probability distribution of expected amplification effects by accounting for uncertainty affecting the relevant parameters. To evaluate the feasibility of the proposed procedure, it has been applied to the Tuscany Region in Central Italy. Unbiasedness of outcomes has been tested by considering detailed microzonation studies available for the considered area. Results of the proposed approach could be easily implemented in extensive seismic risk analyses where detailed seismic microzonation studies are lacking. • A novel methodology is proposed for estimating seismic amplification effects at regional scale from geological maps. • The local seismo-stratigraphy is reconstructed by an automatic GIS-based procedure from the geological map. • Numerical simulations are considered to assess probability distribution of possible seismic amplification values. • Unbiasedness of estimates is assessed by a comparison with seismic microzonation studies in Central Italy. • Outcomes of the present approach can be used for seismic risk assessment at regional scale.