Comparative analysis of geological and seismic microtremors models of a large translational landslide: The case of San Vito Romano (Central Italy)

Abstract

This study investigates the San Vito Romano landslide, a significant but poorly documented gravitational phenomenon in central Italy. The local geological setting is characterized by siliciclastic rock units forming a monocline parallel to the slope, dipping 15–20° eastward. For the first time, a detailed geological model of the landslide was developed by integrating extensive geological-technical inventory data with specific geomorphological field mapping. To further analyze the landslide's dynamics and scale, seismic microtremor measurements were conducted and interpreted using the Horizontal-to-Vertical Spectral Ratio (HVSR) method. To streamline the HVSR data analysis, a semi-automatic visualization tool was developed in the R environment and released as open-source. The integrated interpretation of geophysical and geological models revealed a landslide area of approximately 0.5 km², significantly larger than previously estimated, with a maximum thickness of about 48 m and a total volume of approximately 1 × 10⁷ m³. The primary failure mechanism is identified as a translational rock slide, a common process in sedimentary basins with cuesta morphologies. This research provides the first comprehensive assessment of the San Vito Romano landslide and demonstrates the utility of the HVSR technique in complex geological contexts. It also highlights strategies for integrating geophysical microtremor-based models with geological interpretations, offering insights for future landslide investigations.