New data of active tectonics in Friuli

Friuli represents the area with the highest seismic hazard in the NE Italy. Instrumental and historical earthquakes with M>=5.9, struck this area giving rise to widespread damage (Rovida et al, 2016): 1348 (Mw 6.6), 1511 (Mw 6.3), 1794 (Mw: 5.9); 1873 (Mw 6.3); 1928 (Mw 6); 1936 (Mw 6); 1976 (Mw 6.4 and Mw 5.9). At present the variable NNW-SSE to NNE-SSW oriented accumulating strain with velocities of about 2-3 mm/yr. (Serpelloni et al, 2016) is partitioned between: 1) middle-to-low angle E-W/ENE-WSW and WNW-ESE thrusts (central-western Friuli compressional domain); 2) NW-SE trending strike-slip/transpressive faults (NE Friuli-western Slovenia strike slip domain). During the last years, in the framework of national research programs (CARG-Project, DPC-INGV_S1, ISPRA-Regione FVG), new researches allowed to improve knowledge on the seismotectonics of the area. Because of faults are usually blind, their geometry and kinematic characteristics (e.g. length of the single segments and slip rate) were defined through a multidisciplinary approach, based on geological, morphotectonic, geophysical and paleoseismological surveys. Matching surficial (geological survey, Quaternary geology, morphotectonic analysis with DEM) and deep data (analysis of seismic line supplied by ENI), the main active tectonic structures capable to give rise M>5.5 earthquakes in the Carnic and Julian pre-alpine areas were studied and parametrized. Moreover, paleoseismological investigations were performed in order to reconstruct the late Pleistocene - Holocene tectonic activity of the active faults and to define their main seismotectonic parameters useful to improve seismic hazard assessment of a densely populated region.