Geometria, cinematica e attività pliocenico-quaternaria del sistema di sovrascorrimenti Arba-Ragogna (Alpi Meridionali orientali, Italia NE)

New stratigraphic, geomorphologic and structural data let to delineate the Pliocene - Quaternary activity of the Arba-Ragogna thrust-system that belongs to the front of the eastern Southalpine Chain, a S-SE verging thrust-belt in evolution from middle Miocene to Present. Geometry and kinematic of the Arba-Ragogna thrust-system were recognised both using structural survey and industrial reflection seismic profiles. The system is arranged as a S-SE verging and about WSW-ENE striking imbricate fan of medium to low-angle thrusts. The outermost is the Arba-Ragogna blind thrust. Its long–lasting activity is testified by the angular unconformities between the Upper Miocene, Upper Pliocene and Pleistocene stratigraphic units. A vertical slip rate of about 0.19 mm/a was calculated for the Arba –Ragogna thrust during the last 21000 years. The Arba-Ragogna thrust is one of the seismogenic sources capable to generate earthquakes with M6 in the Veneto-Friuli region, but it cannot be related to historical earthquakes. It indicates that it is one of the “silent” seismogenic source of the eastern Southern Alps.