Integrating litho-stratigraphic and equotip-based analyses to support engineering-geological modelling for site response studies

Abstract

The 2016 earthquake in Central Italy caused varying degrees of damage across Camerino's historic centre (Italy). Two medieval masonry buildings, despite their similar construction characteristics and close proximity, exhibited notable differences in damage extent, highlighting the role of seismic amplification in historic urban areas. This study aims to refine site-specific seismic response analyses by developing a detailed engineering-geological model that integrates litho-stratigraphic, geotechnical, and geophysical data. In-situ mechanical analyses with Equotip on outcropping rocks beneath the buildings, combined with borehole and geophysical data, enabled the identification of key lithological and geotechnical contrasts. These findings revealed significant stratigraphic heterogeneity between the two sites. The first exhibited alternating layers of varying stiffness and velocity, while the second presented a more homogeneous stratigraphy, yet weathered in its shallower portion. These differences influenced site amplification, correlating with greater structural damage at the first site and less deterioration at the second. Variations in litho-mechanical properties, including lower Equotip hardness values and distinct seismic velocities in weathered units, contributed to these discrepancies. This research emphasises the importance of integrating detailed stratigraphic reconstructions with seismic analysis to enhance the resilience of historic structures. The developed methodology provides a transferable framework for seismic risk assessment and retrofitting strategies in other heritage sites. By enhancing subsurface analysis, this approach contributes to cultural heritage preservation in seismically active regions.