Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

100 PATA Days 2024 Fig. 2: The Sibari fault zone (red bands) investigated by means of different approaches, from archaeoseismology and geophysical prospecting to morphotectonics (from Cinti et al., 2024). The three zones enclosed in the yellow lines (1, 2, 3) represent the study areas where the different investigations have been performed. The column (in zone 1) indicates the location of the ancient settlement of Sybaris; the dashed white line encloses the marine terrace mapping area from Alfonsi et al. (2023). Satellite image from Google Earth © Map. T H E M U LT I D I S C I P L I N A R Y A P P R O A C H The fault zone was traced as the envelope of several direct and indirect pieces of evidence resulting in an oblique normal-dextral fault zone, ~NE-SW oriented, extending for a length of about 18 km from the Ionian coastline to Terranova da Sibari (Figure 2). The fault evidence was revealed by applying different types of surveys within the zones shown in Figure 2 (Cinti et al., 2024). Among the main: Zone 1: the archaeoseismological survey on the Roman occupational phase (i.e., second century BCE and sixth/seventh centuries CE) exposed at the Sybaris site (zone 1 in Figure 2) firstly revealed the presence of faulting and liquefaction significantly deforming and rupturing the ancient ruins (Figure 3; Cinti et al., 2015b). The location, geometry (alignment, strike), and kinematics (opening, slip direction) of the surveyed coseismic features define the presence of a 45°-55°- striking faulting zone, i.e., the Sibari fault zone, crossing the settlement and cutting different types of manmade structures and soil. Integration of Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) data with geologic and archaeoseismic data is used to investigate the SFZ at the Sybaris site and its inferred prolongation in the recent sedimentary deposits nearby (Figure 4). Zone 2: the analysis of the streams’ courses revealed abrupt dextral lateral deflections of stream channels running on the steep slopes south of Terranova da Sibari (Figure 5). These have been interpreted as due to cumulative horizontal tectonic slip along the SFZ. Some sub-vertical fault planes and fissures are observed at different locations in correspondence of the channel deflections and have a quite homogeneous strike of N30°-45° and sub-vertical dip. Moreover, waterfalls, knick-points, potholes, and displaced marine terraces are interpreted as additional evidence of the SFZ.