GNGTS 2016 - Atti del 35° Convegno Nazionale

GNGTS 2016 S essione A matrice 33 Conclusions. In the Arquata del Tronto region, a N 10° oriented west-dipping normal fault has been recognised and analysed in detail, in the surroundings of the villages of Piedilama and Pretare. The orientation of the normal fault is different from the trend of the dominant NW-SE extensional features, as it developed almost parallel to the tectonic axis of the previous N10° trending thrust and fold belt features affecting the area of the main Sibillini Mts. Thrust zone. The fault plane juxtaposes two distinct coaxial fold domains. An overturned east-verging anticline was downthrown in the hangingwall of the structure, whereas an east-verging syncline forms the footwall of the fault. This geometry strongly suggests to interpret the normal fault as the product of the negative tectonic inversion of a previous thrust plane. The geological, morphological and geophysical investigations of the structure pointed out clear evidences of its activity during the Late Pleistocene and part of the Holocene. In the frame of a revaluation of the seismic hazard in the area, further investigations (e.g. paleoseismology) should be dedicated to this tectonic feature, in order to exclude any relation between the fault and the seismicity of the area. References Cantalamessa G., Centamore E., Chiocchini U., Di Lorito L., Leonelli M., Micarelli A., Pesaresi A., Potetti M., Taddei L. and VENANZINI D.; 1980: Analisi tettonico-sedimentaria dei «bacini minori» torbiditici del Miocene medio- superiore nell’Appennino umbro-marchigiano e laziale-abruzzese: 9) Il bacino della Laga tra il F. Fiastrone-T. Fiastrella ed il T. Fluvione . Studi Geol. Camerti, 6 , 81-133. Ibs-Von Seht M. and Wohlenberg J.; 1999: Microtremor measurements used to map thickness of soft sediments. Bulletin of the Seismological Society of America, 89 (1), 250-259. ISPRA - CARG Project; 2006: Sheet 314 Montegiorgio . Servizio Geologico d’Italia, 1:50,000 scale. ISPRA - CARG Project; 2009: Sheet 303 Macerata . Servizio Geologico d’Italia, 1:50,000 scale. Pierantoni P., DeianaG. andGaldenzi S.; 2013: Stratigraphic and structural features of the SibilliniMountains (Umbria- Marche Apennines, Italy) . Ital. J. Geosci. (Boll. Soc. Geol. It.), 132 (3), 497-520. doi: 10.3301/IJG.2013.08 Ricci Lucchi F.; 1975: Miocene paleogeography and basin analysis in Periadriatic Apennines . Reprinted from Geology of Italy. P.E.S.L., Tripoli. SESAME; 2004: Guidelines for the implementation of the H/V spectral ratio technique on ambient vibrations: Measurements, processing and interpretation . SESAME European Research Project WP12, deliverable D23.12, at http://sesame-fp5.obs.ujfgrenoble . fr/Deliverables, 2004. Coseismic deformation following the 2016 ML 6 Amatrice earthquake (central Italy): data, analysis and preliminary models from GPS measurements D. Cheloni 1 , A. Avallone 1 , G. Pietrantonio 1 , M. Anzidei 1 , N. D’Agostino 1 , R. Devoti 1 , F. Riguzzi 1 , G. Selvaggi 1 , E. Serpelloni 2 , S. Calcaterra 3 , P. Gambino 3 , R. Giuliani 4 , M. Mattone 4 1 Centro Nazionale Terremoti, Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy 2 Sezione di Bologna, Istituto Nazionale di Geofisica e Vulcanologia, Bologna, Italy 3 Servizio Geofisica, Istituto Superiore per la Protezione e la Ricerca Ambientale, Roma, Italy 4 Ufficio Rischio Sismico, Dipartimento della Protezione Civile, Roma, Italy On August 24, 2016, a ML 6.0 earthquake struck the central Apennines between the towns of Amatrice and Norcia, causing extensive damage to the town of Amatrice and several surroundings villages, and killing 297 inhabitants. The main shock nucleated at a depth of about 7-8 km and was followed by a vigorous aftershock sequence southeast and northwest of the hypocentre, which counts more than 10.000 events at the time of writing, as recorded by the Italian seismic network. The seismic sequence interests a crustal volume extending NW-SE for about 25 km and down to about 15 km of depth. Fault plane solutions published by INGV (Istituto Nazionale di Geofisica e Vulcanologia) for the main shock and largest aftershocks are consistent with normal faulting mechanism striking NW-SE, in agreement with the direction of