http://hdl.handle.net/2122/258 2013-05-21T05:03:30Z http://hdl.handle.net/2122/8663 Title: Integrating geologic fault data into tsunami hazard studies Authors: Basili, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Tiberti, M. M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Kastelic, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Romano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Piatanesi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Selva, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Lorito, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia Abstract: We present the realization of a fault-source data set designed to become the starting point in regional-scale tsunami hazard studies. Our approach focuses on the parametric fault characterization in terms of geometry, kinematics, and assessment of activity rates, and includes a systematic classification in six justification levels of epistemic uncertainty related with the existence and behaviour of fault sources. We set up a case study in the central Mediterranean Sea, an area at the intersection of the European, African, and Aegean plates, characterized by a complex and debated tectonic structure and where several tsunamis occurred in the past. Using tsunami scenarios of maximum wave height due to crustal earthquakes (Mw=7) and subduction earthquakes (Mw=7 and Mw=8), we illustrate first-order consequences of critical choices in addressing the seismogenic and tsunamigenic potentials of fault sources. Although tsunamis generated by Mw=8 earthquakes predictably affect the entire basin, the impact of tsunamis generated by Mw=7 earthquakes on either crustal or subduction fault sources can still be strong at many locales. Such scenarios show how the relative location/orientation of faults with respect to target coastlines coupled with bathymetric features suggest avoiding the preselection of fault sources without addressing their possible impact onto hazard analysis results. 2013-04-18T22:00:00Z http://hdl.handle.net/2122/8661 Title: Biogenic/Abiogenic Hydrocarbons Origin - Possible Role of Tectonically Active Belts Authors: Scalera, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia Editors: Scalera, Giancarlo; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Boschi, Enzo; University of Bologna; Cwojdzinski, Stefan; Polish Geological Survey Abstract: The creation of hydrocarbons is linked to tectono-geologic processes and particularly to orogenesis, rifting, overthrusts, erosion, deposition of sediments, deep gas emissions, etc.. Many have claimed the inadequacy of plate tectonics in linearly explain a number of phenomena involved in hydrocarbons generation and geological processes, and many others have defended the synthesis of hydrocarbons starting from inorganic minerals, proposing di erent geochemical processes. In this paper a possible mechanism for production of abiogenic hydrocarbons is proposed, linking it to a previously proposed orogenic isostatic model. While in plate tectonics the cold slab travels in contact with the lithosphere of the continental side, oxidizing materials faced to oxidizing materials, in this model the hightemperature reducing environment of the undepleted mantle rises up and come in contact with the relatively cold oxidizing lithospheric environment. Non-lithostatic overpressures and a number of chemical reactions are then favoured in this sort of tectonic oxidizingreducing pile, leading to a multiple origin of the hydrocarbons. The actual situation along the Italian Apennines orogenic belt seems in accord to the proposed model in which an important role should have the abiogenic hydrocarbons in particular those produced by the tectonic working at the western margin of the Adriatic plate. However, albeit a continuous accumulation of abiogenic hydrocarbons is witnessed by a number of planetary bodies of the Solar system, still no evaluation of the abiogenic/biogenic hydrocarbons rate is possible on our planet. 2012-11-30T23:00:00Z http://hdl.handle.net/2122/8560 Title: The tectonic puzzle of the Messina area (Southern Italy): Insights from new seismic reflection data Authors: Doglioni, C.; Dipartimento di Scienze della Terra, Universit`a Sapienza, Roma; Ligi, M.; Istituto di Scienze Marine, CNR, Bologna; Scrocca, D.; Istituto di Geologia Ambientale e Geoingegneria, CNR, c/o Dipartimento di Scienze della Terra, Universit`a Sapienza, Roma; Bigi, S.; Dipartimento di Scienze della Terra, Universit`a Sapienza, Roma; Bortoluzzi, G.; Istituto di Scienze Marine, CNR, Bologna; Carminati, E.; Dipartimento di Scienze della Terra, Universit`a Sapienza, Roma; Cuffaro, M.; Istituto di Geologia Ambientale e Geoingegneria, CNR, c/o Dipartimento di Scienze della Terra, Universit`a Sapienza, Roma; D' Oriano, F.; Istituto di Scienze Marine, CNR, Bologna; Forleo, V.; Dipartimento di Scienze della Terra, Universit`a Sapienza, Roma; Muccini, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Riguzzi, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia Abstract: The Messina Strait, that separates peninsular Italy from Sicily, is one of the most seismically active areas of the Mediterranean. The structure and seismotectonic setting of the region are poorly understood, although the area is highly populated and important infrastructures are planned there. New seismic reflection data have identified a number of faults, as well as a crustal scale NE-trending anticline few km north of the strait. These features are interpreted as due to active right-lateral transpression along the north-eastern Sicilian offshore, coexisting with extensional and right-lateral transtensional tectonics in the southern Messina Strait. This complex tectonic network appears to be controlled by independent and overlapping tectonic settings, due to the presence of a diffuse transfer zone between the SE-ward retreating Calabria subduction zone relative to slab advance in the western Sicilian side. 2012-11-30T23:00:00Z http://hdl.handle.net/2122/8558 Title: Active compressional tectonics, Quaternary capable faults, and the seismic landscape of the Po Plain (N Italy) Authors: Michetti, A.; Università dell'Insubria, Dipartimento di Scienza e Alta Tecnologia, Como, Italy; Giardina, F.; Università dell'Insubria, Dipartimento di Scienza e Alta Tecnologia, Como, Italy; Livio, F.; Università dell'Insubria, Dipartimento di Scienza e Alta Tecnologia, Como, Italy; Mueller, K.; University of Colorado, Department of Geological Sciences, Boulder, CO, USA; Serva, L.; ISPRA, Dipartimento Difesa del Suolo/Servizio Geologico d’Italia, Rome, Italy; Sileo, G.; Università dell'Insubria, Dipartimento di Scienza e Alta Tecnologia, Como, Italy; Vittori, E.; ISPRA, Dipartimento Difesa del Suolo/Servizio Geologico d’Italia, Rome, Italy; Devoti, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Riguzzi, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Carcano, C.; Burren Resources Petroleum Ltd, Baza Burren, Burun Field, Balkanabat, Turkmenistan; Rogledi, S.; ENI Exploration and Production, San Donato Milanese (Milan), Italy; Bonadeo, L.; Università dell'Insubria, Dipartimento di Scienza e Alta Tecnologia, Como, Italy; Brunamonte, F.; Università dell'Insubria, Dipartimento di Scienza e Alta Tecnologia, Como, Italy; Fioraso, G.; Istituto di Geoscienze e Georisorse, Consiglio Nazionale delle Ricerche (CNR), Turin, Italy Abstract: It is commonly believed that the Po Plain is an area of low seismic haz- ard. This conclusion is essentially a combination of two factors: (1) the historical record of earthquakes, which shows a relatively small number of events of moderate magnitude, and only two significant earthquakes, which occurred in the Middle Ages; and (2) the lack of ad-hoc research on the geology of earthquakes in this area, as although many studies have highlighted the local Quaternary tectonics, only a very few of them have discussed the observed evidence in terms of seismic hazard. In contrast, the data presented in the present study strongly suggest that the level of earthquake hazard in the Po Plain is comparable to that of the well- known seismic areas of the Apennine range, at least in terms of maxi- mum magnitudes. Indeed, the high population density and the concentration of industrial facilities make the Po Plain today one of the more high-risk areas of the Italian territory. The Po Plain represents the foredeep of two growing mountain belts, the southern Alps and the north- ern Apennines. Recently, modern active tectonics studies have been con- ducted along its margins to the south, along the northern Apennine Piedmont belt, and to the northeast, along the eastern southern Alpine Piedmont belt. However, in the central and western sectors of the Po Plain, where the south-verging western southern Alpine front links up with the north-verging Monferrato, Emilia and Ferrara arcs, the Qua- ternary history of tectonic deformation and faulting are still relatively poorly understood. These lie beneath the relatively flat alluvial surface of the Po River, and provide the evidence for paleoseismicity and the result- ing seismic hazard. In this review, we compile the data from the literature to reassess the style and magnitude of the ongoing crustal deformation and the associated earthquake faulting. This includes detailed informa- tion on historical and instrumental seismicity, extensive subsurface in- formation from the ENI industrial exploration, structural interpretation of three regional seismic reflection profiles, analysis of novel global posi- tioning system data, field mapping at selected key areas, and new paleo- seismological investigations. We show that along the western southern Alpine belt between Lake Garda and Lake Maggiore, the active tectonic setting is characterized by a segmented belt of fault-propagation folds. These are 50 km wide, and are controlled by the growth of out-of-se- quence, 10-to-20-km-long, north and south verging thrusts. Regional global positioning system data show ongoing shortening rates of the order of 1 mm/yr. Quaternary fault slip rates typically range between 0.2 mm/yr and 0.4 mm/yr. Pleistocene shortening is obvious not only along the western southern Alpine outer fronts that are buried beneath the Po Plain, but also along the south Alpine foothills between Brescia and Varese. Similar styles and rates of active folding and thrusting have also been documented along the frontal sector of the northern Apennine arcs, from Torino to Ferrara, and along the base of the Apennine mountain front between Piacenza and Bologna. We selected the Brescia and Como sectors in the western southern Alps and the Monferrato and Mirandola structures in the northern Apennines as examples to illustrate the seismic landscape of the study area, in terms of typical active structural, geo- morphic and paleoseismic features. We argue that the level of earthquake hazard in the Po Plain is comparable to that of the Apennine range. On May 20, 2012, a few days after this review was formally accepted for pub- lication, a M W 5.9 earthquake ruptured the Mirandola structure. The seismic sequence following this mainshock is ongoing, and we have added further information about this event (updated on June 3rd, 2012), which substantially confirms the conclusions arrived at here. 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8554 Title: GPS observations of coseismic deformation following the May 20 and 29, 2012, Emilia seismic events (northern Italy): data, analysis and preliminary models Authors: Serpelloni, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Anderlini, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Avallone, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Cannelli, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Cavaliere, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Cheloni, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; D'Ambrosio, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; D'Anastasio, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Esposito, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Pietrantonio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Pisani, A. R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Anzidei, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Cecere, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; D'Agostino, N.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Del Mese, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Devoti, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Galvani, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Massucci, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Melini, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Riguzzi, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Selvaggi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Sepe, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia Abstract: In May-July 2012, a seismic sequence struck a broad area of the Po Plain Region in northern Italy. The sequence in- cluded two ML >5.5 mainshocks. The first one (ML 5.9) oc- curred near the city of Finale Emilia (ca. 30 km west of Ferrara) on May 20 at 02:03:53 (UTC), and the second (ML 5.8) occurred on May 29 at 7:00:03 (UTC), about 12 km south- west of the May 20 mainshock (Figure 1), near the city of Mirandola. The seismic sequence involved an area that ex- tended in an E-W direction for more than 50 km, and in- cluded seven ML ≥5.0 events and more than 2,300 ML >1.5 events (http://iside.rm.ingv.it). The focal mechanisms of the main events [Pondrelli et al. 2012, Scognamiglio et al. 2012, this volume] consistently showed compressional kinematics with E-W oriented reverse nodal planes. This sector of the Po Plain is known as a region charac- terized by slow deformation rates due to the northwards mo- tion of the northern Apennines fold-and-thrust belt, which is buried beneath the sedimentary cover of the Po Plain [Pi- cotti and Pazzaglia 2008, Toscani et al. 2009]. Early global po- sitioning system (GPS) measurements [Serpelloni et al. 2006] and the most recent updates [Devoti et al. 2011, Bennett et al. 2012] recognized that less than 2 mm/yr of SW-NE short- ening are accommodated across this sector of the Po Plain, in agreement with other present-day stress indicators [Mon- tone et al. 2012] and known active faults [Basili et al. 2008]. In the present study, we describe the GPS data used to study the coseismic deformation related to the May 20 and 29 mainshocks, and provide preliminary models of the two seismic sources, as inverted from consensus GPS coseismic deformation fields. 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8552 Title: Coseismic deformation and source modeling of the May 2012 Emilia (Northern Italy) earthquakes Authors: Pezzo, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Merryman Boncori, J. P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Tolomei, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Salvi, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Atzori, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Antonioli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Trasatti, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Novali, F.; Tele-Rilevamento Europa - T.R.E. srl; Serpelloni, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Candela, L.; Agenzia Spaziale Italiana, Unità Osservazione della Terra; Giuliani, R.; Dipartimento della Protezione Civile, Ufficio Rischio Sismico Abstract: On May 20th, 2012, an ML 5.9 earthquake (Table 1) occurred near the town of Finale Emilia, in the Central Po Plain, Northern Italy (Figure 1). The mainshock caused 7 casualties and the collapse of several historical buildings and industrial sheds. The earthquake sequence continued with diminishing aftershock magnitudes until May 29th, when an ML 5.8 earthquake occurred near the town of Mirandola, ~12 km WSW of the mainshock (Scognamiglio et al., 2012). This second mainshock started a new aftershock sequence in this area, and increased structural damage and collapses, causing 19 more casualties and increasing to 15.000 the number of evacuees. Shortly after the first mainshock, the Department of Civil Protection (DPC) activated the Italian Space Agency (ASI), which provided post-seismic SAR Interferometry data coverage with all 4 COSMO-SkyMed SAR satellites. Within the next two weeks, several SAR Interferometry (InSAR) image pairs were processed by the INGV-SIGRIS system (Salvi et al., 2012), to generate displacement maps and preliminary source models for the emergency management. These results included continuous GPS site displacement data, from private and public sources, located in and around the epicentral area. In this paper we present the results of the geodetic data modeling, identifying two main fault planes for the Emilia seismic sequence and computing the corresponding slip distributions. We discuss the implication of this seismic sequence on the activity of the frontal part of the Northern Apennine accretionary wedge by comparing the co-seismic data with the long term (geological) and present day (GPS) velocity fields. 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8550 Title: New kinematic constraints of the western Doruneh fault, north-eastern Iran, from interseismic deformation analysis Authors: Pezzo, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Tolomei, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Atzori, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Salvi, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Shabanian, E.; CEREGE - AIX-MARSEILLE UNIVERSITE; Bellier, O.; CEREGE - AIX-MARSEILLE UNIVERSITE; Farbod, Y.; CEREGE - AIX-MARSEILLE UNIVERSITE Abstract: We used the SBAS DInSAR analysis technique to estimate the interseismic deformation along the western part of the Doruneh fault system (DFS), northeastern Iran. We processed 90 ENVISAT images from four different frames from ascending and descending orbits. Three of the ground velocity maps show a significant interseismic signal. Using a simple dislocation approach we model 2-D velocity profiles concerning three InSAR data set relative to the western part of the DFS, obtaining a good fit to the observations. The resulting model indicates that a slip rate of ∼5mmyr−1 accumulates on the fault below 10 km depth, and that in its western sector the Doruneh fault is not purely strike-slip (left-lateral) as in its central part, but shows a significant thrust component. Based on published geological observations, and assuming that all interseismic deformation is recovered with a single event, we can estimate a characteristic recurrence interval between 630 and 1400 yr. 2012-05-20T22:00:00Z http://hdl.handle.net/2122/8516 Title: Active deformation along the northern margin of the Hyblean Plateau (SE Sicily) from GPS and geological data Authors: Bonforte, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Catalano, S.; Università degli studi di Catania; Maniscalco, R.; Università degli studi di Catania; Romagnoli, G.; Università degli studi di Catania; Sturiale, G.; Università degli studi di Catania; Tortorici, G.; Università degli studi di Catania Abstract: A diffuse fragmentation of the Nubia-Eurasia tectonic boundary, due to the propagation of distinct extensional belts, has characterised the post-collision evolution of the region. In this frame, the Hyblean Plateau was affected, since about 1.5 Ma B.P., by the propagation of the the roughly N-S trending Siculo-Calabrian Rift Zone (SCRZ in Fig.1a; MONACO & TORTORICI, 2000), an extensional belt that extends from the onshore of southern Calabria to the SE Sicily. In the Hyblean plateau the propagation of the rift zone caused the reactivation of the main previous discontinuity. The earlier SE Sicily branch of the rift zone, in fact, propagated from the Ionian coast to the Scicli Line, causing the collapse of the NEtrending Scordia-Lentini Graben, at the northern margin of the plateau. This extensional basin represents an half-graben, which is controlled by a SE-facing master fault. 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8496 Title: Are the source models of the M7.1 1908 Messina Straits earthquake reliable? Insights from a novel inversion and a sensitivity analysis of levelling data Authors: Aloisi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Bruno, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Cannavo', F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Ferranti, L.; Dipartimento di Scienze della Terra, Universita' di Napoli; Mattia, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Monaco, C.; Dipartimento di Scienze Geologiche, Universita' di Catania; Palano, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia Abstract: For decades, many authors have attempted to define the location, geometry and kinematics of the causative fault for the 1908 December 28, M 7.1 earthquake that struck the Messina Straits between Sicily and Calabria (southern Italy). The coseismic displacement caused a predominant downwarping of the Straits and small land uplift away from it, which were documented by levelling surveys performed 1 yr before and immediately after the earthquake. Most of the source models based on inversion of levelling data suggested that the earthquake was caused by a low angle, east-dipping blind normal fault, whose upper projection intersects the Earth surface on the Sicilian (west) side of the Messina Straits.An alternative interpretation holds that the causative fault is one of the high-angle, west-dipping faults located in southern Calabria, on the eastern side of the Straits, and may in large part coincide with the mapped Armo Fault. Here, we critically review the levelling data with the aim of defining both their usefulness and limits in modelling the seismogenic fault. We demonstrate that the levelling data alone are not capable of discriminating between the two oppositely dipping fault models, and thus their role as a keystone for modellers is untenable. However, new morphotectonic and geodetic data indicate that the Armo Fault has very recent activity and is accumulating strain. The surface observations, together with appraisal ofmacroseismic intensity distribution, available seismic tomography and marine geophysical evidence, lends credit to the hypothesis that the Armo and possibly the S. Eufemia faults are part of a major crustal structure that slipped during the 1908 earthquake. 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8475 Title: Very detailed seismic pattern and migration inferred from the April 2010 Pietralunga (northern Italian Apennines) micro-earthquake sequence Authors: Marzorati, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Massa, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Cattaneo, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Monachesi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Frapiccini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia Abstract: We propose a very detailed picture of the seismicity occurring in the proximity of the Alto Tiberina Low Angle Normal Fault (ATF, Northern Italian Apennines) by presenting the pattern and evolution of a seismic sequence that occurred on the hanging wall of the ATF in the first months of 2010 and that was characterized by about 1000 events with ML ranging from -0.7 to 3.8. In order to capture the rupture kinematics of the investigated area, a cross-correlation technique was at first applied to calculate very accurate time shifts among the events of the sequence and then to relocate them. Considering the many factors that can affect the accuracy of a routine event location, the whole sequence was relocated with the double-difference method, including both absolute travel-time measurements and cross-correlation differential travel-times. The new locations confirm that seismic activity is mainly arranged along a NW-SE oriented structure, ranging in depth from 4 to 6 km and dipping towards North East with an angle of about 65°. A further analysis of waveforms similarity was performed at a reference station by merging the capability of the cross-correlation technique and the bridging algorithm. The analysis allows us to group events into several earthquake families (from now on multiplets), 11 of which include at least 10 events with a cross-correlation value higher than 0.9. The detected mutiplets allow us to emphasize the spatial and temporal migration of the sequence occurred along a 307°N strike direction with an averaged propagation velocity of about 0.4 km/day. The normal focal mechanisms obtained from the events with ML≥2 validate the supposed extensional tectonic regime of the investigated area. The main nodal planes, characterized by strikes ranging in 312°±12 and dips about -90°, are consistent with the spatial evolution of the aftershocks. 2011-12-31T23:00:00Z