Seismic velocity model and near-surface geology at Mycenaean Tiryns, Argive Basin, Peloponnese, Greece
A near-surface seismic refraction tomography survey was completed in the surroundings of the Mycenaean citadel of Tiryns in the Argive Basin, Peloponnese, Greece. The survey encompassed 11 hectares at the Tiryns citadel, an archaeological site listed by the United Nations Educational, Scientific and Cultural Organization as world heritage with over 120 years of excavation history. Site characterization of the shallow subsurface was performed using two-dimensional seismic refraction tomography of compressional (P) and horizontally polarized shear (SH) wave data along 12 and 9 profiles, respectively. The interpretation of the seismic refraction results is complemented by available archaeological stratigraphy, stratigraphic logs, and new structural data of the exposed bedrock. The tomograms show a transition from unconsolidated fine alluvium at the surface to consolidated clays and silts to hard limestone bedrock. The soil–bedrock boundary dips away from the citadel, influencing the geometry of overlying soils into wedges. Based on twodimensional tomograms of P- and SH-wave velocities, the Poisson ratio, shear modulus, Young’s modulus, and bulk modulus were estimated for a four-layer geotechnical model, which will be used to study seismic site effects. The rock mass quality index of the bedrock at Tiryns is classified as fair to very poor.