GNGTS 2013 - Atti del 32° Convegno Nazionale

Cozzo S. Elia site. Cozzo S. Elia site is located on northern gently dipping slope of the Cozzo S. Elia hill; the fault strand is here expressed as a scarp smoothed by intense ploughing (Fig. 2a). Here we acquired a tomographic section (Wenner array; spacing 5 m) oriented ca. NE-SW and perpendicular to the scarp direction (Fig. 2b). The section displays a small resistivity range, spanning between 2 and 150 Ohm·m. This possibly reflects lateral changes in the presence of a relatively shallow water-table. The resistivity pattern depicted in the central part of the section is likely consistent with the presence of a fault showing a SW side downthrown of ca. 4-5 m. Resistivity absolute values are not referable to bedrock but the low values are typical of fine-grained sediments (fine sands, silts and clays), thus the inferred offset possibly occurs on recent soft deposits (i.e. fine grained alluvial cover). Castrovillari site. The Castro- villari site (Fig. 1b) is located across a stream incision transverse to one of the southern scarps of the Castrovil- lari scarp system. The fault is here expressed by a scarp that is built in fan delta depos- its, characterized by thick packag- es of sand and silt, alternating with strongly cemented conglomerates and gravels. A fault zone (F1 in Fig. 2) outcrops at the modified edge of the valley in correspondence of the upper part of the scarp. The main fault trace (dipping N250/70) shows dip-slip displacement (SW-side down) of fan delta deposits. To the SW another fault (F2) crops out and puts in lateral contact conglomerates and sandy deposits of the fan delta sequence. We performed three to- mographic sections, acquired within the valley floor perpendicularly to the fault trending and centered on the fault trace. In order to detect both horizon- tally and vertically oriented subsur- face structures, the sections were ac- quired with different configurations (i.e. dipole-dipole, Wenner and Wen- ner-Schlumberger) and spacing. Fig. 1 – Regional seismotectonic framework for the Pollino region: a) main Quaternary faults (ITHACA database; e.g. Michetti et al. 2000a) and historical and instrumental seismicity from XI Sec. A.D. to 2006 (CPTI Catalogue, Rovida et al. 2011); b) GOOGLE™ image of the Castrovillari basin: Castrovillari and Pollino faults are indicated as well as the study sites. 110 GNGTS 2013 S essione 1.1