Exploring the three-dimensional architecture of the cassino basin for local seismic response analysis.

Seismic amplifications depend on the depth of the bedrock, as well as the stratigraphy and dynamic properties of the soil deposits. It is essential to accurately quantify these properties and their uncertainties to assess seismic risk at an urban scale. This paper uses geophysical microtremor measurements, geological and geotechnical surveys, as well as analytical and geostatistical techniques to characterize the complex shape of the bedrock in the Cassino basin, a Quaternary intermontane basin in central Italy. Boreholes, some reaching depths of up to 180 meters, and microtremor measurements are combined to identify the depth of the bedrock by revealing the sharp impedance contrast between the sedimentary/arenaceous bedrock and the soft Quaternary infilling. Understanding the depth of the bedrock is crucial as it influences the propagation of seismic waves to the ground level and is the first step in assessing seismic hazard in the area.