# 2-D Seismic Response Analysis of a Slope in the Tyrrhenian Area (Italy)
## 2 Site Characterization
### Investigation Program and Geotechnical Soil Properties  
The Regional Department of the Civil Defense put in many efforts in terms of studies and analyses that obtained precious information for a detailed geotechnical characterization of the Caronia area [21]. The static and dynamic geotechnical characterization of soils in the Contrada Lineri of Caronia was performed within an investigation test site with a surface of about 13 hectares; Figure 4 shows the layout of test sites with the location of geotechnical boreholes and piezometers. The study area reached a maximum depth of 30 m. Laboratory tests (moisture content; soil unit weight; specific gravity; grain size analysis; Arterberg limits; direct shear test) were performed on undisturbed samples [22]. To evaluate the geotechnical characteristics of soils, the following in situ and laboratory tests were performed in the area: n. 11 Boreholes, n. 10 Piezometers, n. 5 Inclinometric Measurements, n. 3 Down-Hole tests (DHT), n. 7 Seismic Tomography Tests, n. 2 Multichannel Analysis of Surface Waves (MASW), n. 12 Direct Shear Tests (DST). Figure 3: Geological map of the study area [20]. Based on of the data available from boreholes (Table 1), soil profiles of the ground beneath the Caronia test sites could be designed. Summarizing the borehole results, it is possible to define four soil classes, namely: plastic structureless clays, brown color structureless clays, gray color structureless clays and argillites. The water level was in the range 8.30-11.20 m. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Borehole** & **D** & **Soil Profile** & **V\({}_{\text{S}}\)** \\  & **[m]** & & **[m/s]** \\ \hline BH105 & 0.00–4.00 & Debris: conglomerate screed, boulders and chaotic material. & \textless{}260 \\ \hline  & & Tobacco brown clays, to the touch plastic and from medium & \\ BH105 & 4.00–15.50 & consistent to consistent in the lower part (10.50–15.50 m); at times & \textless{}350 \\  & & there are clay levels; overall, when cut, they present themselves with & \\  & & ferrous, rust-colored and alternatively gray alterations. & \\ \hline BH105 & 15.50–31.00 & Dark gray clay with very consistent sections, alternating with & \textless{}450 \\  & & fractured and flattened layers; moreover, there are rare levels of clay & \textless{}600 \\  & & with plastic behavior and dark color. & \\ \hline BH3 & 0.00–4.00 & Plastic structureless clays (landslide debris). & \textless{}260 \\ \hline BH3 & 4.00–6.00 & Chaotic structureless clay with occasional compact clay levels of & \\  & & brown color with plastic consistency and poor characteristics. & \textless{}350 \\ \hline BH3 & 6.00–15.50 & Chaotic structureless clay with occasional compact clay levels of gray & \textgreater{}350 \\  & & color with plastic consistency and mediocre characteristics. & \textless{}450 \\ \hline BH3 & 15.50–31.00 & Argillites with lytic tracts and sub-vertical fractures, dark gray or & \textgreater{}450 \\  & & blackish in color with mediocre characteristics. & \textless{}600 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Soil profile for Caronia area. Figure 4: Layout of test sites with the location of geotechnical boreholes and piezometers. The stratigraphic columns were obtained directly by the study of topographical profiles. This was done by trying to predict as accurately as possible what the soil profile looked like beneath the surface from the information available from the stratigraphic columns, linking corresponding strata with neighboring stratigraphic columns where possible. Once each stratum was completed, the corresponding lithological design was assigned (Figure 5). Based on the laboratory tests, the typical range of physical characteristics, index properties and strength parameters of the deposits mainly encountered in these areas are reported in Tables 2 and 3.