GNGTS 2014 - Atti del 33° Convegno Nazionale

depth, that have different geological-technical characteristics and that correspond to the present- day areas of the fluvio-lacustrine plane and of the base of the slopes. The first area corresponds mainly to the inner part of the basin and shows a depocenter deep more than 435 m and filled by a thick (≥ 400 m) fine lacustrine succession, on which lay sandy-gravel terraced alluvial deposits of the Middle-Upper Pleistocene (Terrazza Alta di Sulmona), about 30-40 m thick (Fig. 1), in turn cut and filled by younger alluvial deposits (Upper Pleistocene-Holocene) (Fig. 1). The second macroarea, in proximity of the carbonate ridges at the border sides of the basin, shows a very different lithostratigraphic and morphological setting. Here the clastic supply from slope and alluvial fans has guided the sedimentation and controlled the complex lateral and vertical transitions with the fine lacustrine deposits within the basin. Fig. 1 schematizes the complex setting of the western slope of the Mt. Morrone. It is bounded by an important active and capable normal fault that determines the contact between the Mesozoic carbonate bedrock, strongly cataclastic, and the slope deposits passing laterally to the terraced alluvial deposits of the Middle-Upper Pleistocene. At the base of the slope, these deposits are probably displaced by an inner splay of the major boundary fault. The main uncertainties regard the area included between the two tectonic structures where the performed noise measurements do not show any frequency of amplification. This kind of response could be attributed either to the presence of the carbonate bedrock in the near surface (eg., downthrown fault block) or to a thick sequence of slope deposits, probably cemented, above the carbonate bedrock. Considering that within the basin area the carbonate substratum has never been intercepted by any borehole, noise data provided useful constraints on the geometry between the continental succession and the bedrock within the basin. Noise measurements have been carried out in correspondence of 43 sites in the Sulmona basin, with the aim of evaluating their resonant Fig. 1 – Geologic cross-section across the Sulmona tectonic basin. HVSR diagrams are also reported above the topography. See text for explanation. See Fig. 2 for cross-section location. GNGTS 2014 S essione 2.2 263