GNGTS 2016 - Atti del 35° Convegno Nazionale

GNGTS 2016 S essione A matrice 73 (helikite and un-manned aerial vehicles - UAVs). Moreover, a web-based data sourcing was activated to gather geological information from local inhabitants. The whole collected data have been stored in a georeferenced-database, in GIS environment, managed on ESRI ArcGIS platform (for details see EMERGEO Working Group, 2012). The survey have involved about 50 researchers and technicians of the INGV that have investigated an area of about 750 km 2 , recording more than 3200 observations from Castelluccio di Norcia at north, to the Campotosto Lake to the south, mainly focusing along the Mt.Vettore and Mts. Della Laga fault systems (Fig. 1). The geological dataset consists of 230 coseismic fractures (<1 cm displacements), 2600 coseismic ruptures (64 displacements >1cm), 160 medium to small-sized coseismic landslides, 28 coseismic features related to the shaking (e.g. clast extrusions, soil remobilization, etc.), and other observation sites where we documented the lack of effects. In addition, a fracturing pattern has been recognized in the trench sector and along the upper limit of 3 DGSD (deep-seated gravitational slope deformations) between the villages of Castelluccio and Norcia as result of coseismic-induced acceleration. First results. The characteristics and the distribution of the coseismic effects related to the August 24, 2016 Amatrice earthquake allow us to identify two different areas: The Laga Mts. Fault System to the south, and the Mt. Vettore Fault System to the north. In the northern portion of the Laga Mts. Fault System, sparse and discontinuous coseismic ruptures few tens of meters long, were observed. They are characterized by the absence of any prevalent geometric pattern and by very small offsets. Any coseismic effect and lack of clear fracturing at surface were observed on central-southern portion of this fault. Along the Mt. Vettore Fault System sector, a localized dataset of coseismic ruptures with offset was surveyed. The main characteristics are: length of the continuous alignment of 5.2 km; general regularity of the structural pattern; constant kinematics with the SW side down; structural pattern, kinematics and offset distribution not influenced by topography and morphology; rupture crossing both bedrock and unconsolidated deposits. All these features lead to hypothesize that the observed displacements could be defined as primary surface faulting (Fig. 2). Fig. 2 – Coseimic ruptures observed along the Mt. Vettore Fault.