1,721,099 research outputs found
SISMO - Storia sISmica di sito di ManOppello
No full textDPC-INGV S2Unpublished3.2. Tettonica attivaope
SISMO - Storia sISmica di sito di ManOppello
No full textDPC-INGV S2Unpublished3.2. Tettonica attivaope
DISS 3.1.1: Seismogenic Source ITCS079 - Shallow Abruzzo Citeriore Basal Thrust. INGV-DISS version 3
No full textLate Quaternary extension of the southern Adriatic foreland (Italy): evidence from joint analysis
No full textThe Adriatic foreland of the Apennines comes ashore only in Apulia (easternmost Italy). The Southern Apulia, our study area, lacks any structural analysis devoted to define its recent-to-active tectonics. Throughout the Quaternary, this region was affected by mild brittle deformation with rare faults, characterised by small displacement, and widespread extension joints, frequently organised in sets. Therefore, we conducted a quantitative and systematic analysis of the joint sets affecting Quaternary deposits, by applying an inversion technique ad hoc to infer the orientation and ratio of the principal stress axes (R). Within a general extensional regime, we recognised three deformational events of regional significance. The oldest event, constrained to the early and middle part of the Middle Pleistocene, is characterized by variable direction of extension and R values between 0.64 and 0.99. The penultimate event, dated late Middle Pleistocene, is characterized by an almost uniaxial tension, with a horizontal σ3 striking ~N43°; R is high, between 0.85 and 0.99. The most recent event is characterized by the lowermost R values, that never exceed 0.47 and are commonly <0.30, indicating a sort of horizontal ‘radial’ extension. This event is not older than the Late Pleistocene and possibly reflects the active stress field still pervading the entire study area
Ground Shaking Scenarios: The 8 September 1905 Earthquake in the Gulf of Sant’Eufemia, Offshore Western Calabria (Southern Tyrrhenian Sua, Italy)
No full textUnveiling the Sources of the Catastrophic 1456 Multiple Earthquake: Hints to an Unexplored Tectonic Mechanism in Southern Italy
No full textWe revisited data related to the 1456 seismic crisis, the largest earthquake to have ever occurred in peninsular Italy, in search of its causative source(s). Data about this earthquake consist solely of historical reports and their intensity assessment.
Because of the age of this multiple earthquake, the scarcity and sparseness of the data, and the unusually large damage area, no previous studies have attempted to attribute the 1456 events to specific faults. Existing analytical methods to identify a likely source from intensity data also proved inappropriate for such a sparse dataset, since historical evidence suggests that the cumulative damage pattern contains at least three widely separated events.
We subdivided the 1456 damage pattern into three independent mesoseismal areas; each of these areas falls onto east–west tectonic trends previously identified and marked by deep (>10 km) right-lateral slip earthquakes. Based on this evidence we propose (1) that the 1456 events were generated by individual segments of regional east–west structures and are evidence of a seismogenic style that involves oblique dextral reactivation of east–west lower crustal faults; (2) that each event may have triggered subsequent but relatively distant events in a cascade fashion, as suggested by historical accounts; hence (3) that the 1456 sequence reveals a fundamental but unexplored mechanism of tectonic deformation and seismic release in southern Italy. This style dominates the region that lies between the northwest–southeast system of large extensional faults straddling the crest of the southern Apennines and the buried outer front of the chain.
Although the quality of the available information concerning the 1456 earthquake is naturally limited, we show that the overlap of the damage distribution, the orientation and characteristics of regional tectonic structures, the seismicity patterns, and the focal mechanisms all concur with our interpretations and would be difficult to justify otherwise.Published725-748JCR Journalope
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Low seismicity hints at the accommodation zone between large seismogenic sources in the central-southern Apennines (Italy)
No full textWe analyze seismicity occurred in the 2007-2011 period on the border between the NW-SE striking central and southern Apennines (central Italy), characterized by the transition between two aligned antithetic normal fault systems. These regional fault sets include large seismogenic sources, causative of major earthquakes in the area, SW-dipping to the north, NE-dipping to the south, respectively. We (a) investigate the accommodation zone and the linkage between the SW-dipping Aremogna-Cinque Miglia (to the north) and NE-dipping Boiano Basin (to the south) sources, and (b) test whether the transfer zone model applies to the central-southern Apennines border.
The epicentral distribution of the relocated earthquakes (1.63.0) show both dip-slip and strike-slip motion, with T-axes NE-SW striking, consistent with the large-scale stress field controlling the Apennine Chain. Focal mechanisms of the swarms’ most energetic events show dip-slip motion, with T-axes ~NNW-SSE striking, coherent with local NW-SE extension hypothesized in this sector.
Based on spatiotemporal characteristics of the seismicity, geometry and kinematics of active faulting in the region, and results from previous geophysical studies, we hypothesize (a) an accommodation zone between the Aremogna-Cinque Miglia and Boiano Basin sources, and (b) the activity of such linkage along the Ortona-Roccamonfina Line. We infer that the dip switch between the two antithetic seismogenic normal fault systems could also result from the rheologic and tectonic control exerted by the passage between two diverse paleogeographic domains composing the border between the central and southern Apennines.MIUR (Italian Ministry of Research) FIRB Project “Piattaforma di ricerca multidisplinare su terremoti e vulcani (AIRPLANE)”Submitted3.2. Tettonica attivaJCR Journalreserve
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