Raised Holocene paleo-shorelines along the Capo Schiso coast, Taormina: New evidence of recent co-seismic deformation in northeastern Sicily (Italy)

摘要

Detailed mapping of geomorphological, biological and archaeological sea-level markers around the Capo Schiso volcanic headland, a few kilometers south of Taormina, north-eastern Sicily, has documented the occurrence of three Holocene paleo-shorelines raised at different altitudes. The uppermost shoreline (PS1) is represented by a fossiliferous beach deposit that is heavily eroded and only few small sections, at elevations ranging between ～3 and ～5 m above the present sea-level, are visible. The middle shoreline (PS2) was found at a maximum altitude of ～3 m and is represented by algal rims, remnants of barnacle bands and vermetid concretions, and by a fossiliferous beach deposit. The lowermost shoreline (PS3) includes remnants of algal rims, vermetid concretions, fossil barnacle bands and a beachrock, and reaches an elevation of 1.60-1.80 m. New radiocarbon dating results, integrated with published ages from nearby paleo-shoreline outcrops, constrains for the Taormina region an average uplift rate of 1.7-1.8 mm/yr in the last 5ka, and the occurrence of three co-seismic uplift events at 4.4-3.9 ka, 2.1-1.8 ka and ≤1.0ka ago. Abrupt displacements are tentatively attributed to footwall uplift along an offshore normal fault, but further investigations are needed to better constrain the causative source of past earthquakes. Notwithstanding, based on coastal tectonic analysis, this paper provides a new assessment of age and recurrence time of Holocene earthquakes in a historically strong seismogenic area.