Remarks on Factors influencing Shear Wave Velocities and their role in evaluating Susceptibilities to Earthquake-triggered Slope Instability: case study for the Campania area (Italy)

Shear wave velocities have a fundamental role in connection with the mitigation of seismic hazards, as their low values are the main causes of site amplification phenomena and can significantly influence the susceptibility of a territory to seismic-induced landslides. The shear wave velocity and modulus of each lithological unit are influenced by factors such as the degree of fracturing and faulting, the porosity, the clay amount and the precipitation, with the latter two influencing the unit's water content. In this paper we discuss about how those factors can affect the Vs values and report the results of different analyses which quantify the reduction in the rocks' Vs and shear modulus values connected to the presence of clay and water. We also show that significant results in assessing seismic-induced slope failure susceptibility for land planning targets could be achieved through a careful evaluation, based only on literature studies, of the geo-lithological and geo-seismic features of the study area.