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Stanghellini, G.
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- PublicationOpen AccessStyles and rates of deformation in the frontal accretionary wedge of the Calabrian Arc (Ionian Sea): controls exerted by the structure of the lower African plate(2017)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Bortoluzzi, G.; Institute of Marine Science CNR ISMAR-BO ;Polonia, A.; Institute of Marine Science CNR ISMAR-BO ;Torelli, L.; Department of Physics and Earth Sciences, University of Parma ;Artoni, A.; Department of Physics and Earth Sciences, University of Parma ;Carlini, M.; Department of Physics and Earth Sciences, University of Parma ;Carone, S.; Istituto Idrografico della Marina ;Carrara, G.; Institute of Marine Science CNR ISMAR-BO ;Cuffaro, M.; Istituto di Geologia Ambientale e Geoingegneria, CNR ;Del Bianco, F.; Institute of Marine Science CNR ISMAR-BO ;D'Oriano, F.; Institute of Marine Science CNR ISMAR-BO ;Ferrante, V.; Istituto Idrografico della Marina ;Gasperini, L.; Istituto Idrografico della Marina ;Ivaldi, R.; Istituto Idrografico della Marina ;La Terra, A.; Istituto Idrografico della Marina ;Ligi, M.; Institute of Marine Science CNR ISMAR-BO ;Locritani, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Muccini, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Mussoni, P.; Department of Physics and Earth Sciences, University of Parma ;Priore, F.; Institute of Marine Science CNR ISMAR-BO ;Riminucci, F.; Institute of Marine Science CNR ISMAR-BO ;Romano, S.; Institute of Marine Science CNR ISMAR-BO ;Stanghellini, G.; Institute of Marine Science CNR ISMAR-BO; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; The Calabrian Arc is a narrow subduction-rollback system resulting from Africa/Eurasia plate convergence. We analysed the structural style of the frontal accretionary wedge through a multiscale geophysical approach. Pre-stack depth-migrated crustal-scale seismic profiles unravelled the overall geometry of the subduction complex; high-resolution multi-channel seismic and sub-bottom CHIRP profiles, together with morpho-structural maps, integrated deep data and constrained the fine structure of the frontal accretionary wedge, as well as deformation processes along the outer deformation front. We identified four main morpho-structural domains in the western lobe of the frontal wedge: the proto-deformation area at the transition with the abyssal plain; two regions of gentle and tight folding; a hummocky morphology domain with deep depressions and intervening structural highs; a highstanding plateau at the landward limit of the salt-bearing accretionary wedge, where the detachment cuts through deeper levels down to the basement. Variation of structural style and seafloor morphology in these domains are related to a progressively more intense deformation towards the inner wedge, while abrupt changes are linked to inherited structures in the lower African plate. Our data suggest focusing of intense shallow deformation in correspondence of deeply rooted faults and basement highs of the incoming plate. Back-arc extension in the Southern Tyrrhenian Sea has recently ceased, producing a slowdown of slab rollback and plate-boundary re-organization along trans-tensional lithospheric faults segmenting the continental margin. In this complex setting, it is not clear if the accretionary wedge is still growing through frontal accretion. Our data suggest that shortening is still active at the toe of the wedge, and uplift rates along single folds are in the range of 0.25-1.5 mm/yr. An unconformity within the Plio-Quaternary sediments suggests a discontinuity in sedimentation and tectonic processes, i.e. a slowdown of shortening rate or an increase in sedimentation rate, but not a real inactivation of frontal accretion, which still contributes to the migration of the outer deformation front towards the foreland.505 579 - PublicationRestrictedMagnetic and seismic reflection study of Lake Cheko, a possible impact crater for the 1908 Tunguska Event(2012-05-12)
; ; ; ; ; ; ; ;Gasperini, L.; CNR-Ismar Bologna ;Cocchi, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Stanghellini, C.; INAF-Bologna ;Stanghellini, G.; CNR-Ismar Bologna ;Del Bianco, F.; CNR-Ismar Bologna ;Serrazanetti, M.; CNR-Ismar Bologna ;Carmisciano, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; ; ; ; A major explosion occurred on 30 June 1908 in the Tunguska region of Siberia, causing the destruction of over 2,000 square km of taiga; pressure and seismic waves detected as far as 1,000 km away; bright luminescence in the night skies of Northern Europe and Central Asia; and other unusual phenomena. This “Tunguska Event” is probably related to the impact with the Earth of a cosmic body that exploded about 5-10 km above ground, releasing in the atmosphere 10-15 Mton of energy. Fragments of the impacting body have never been found, and its nature (comet or asteroid) is still a matter of debate. We report here results from a magnetic and seismic-reflection study of a small (~500 m diameter) lake, Lake Cheko, located about 8 km NW of the inferred explosion epicenter, that was proposed to be an impact crater left by a fragment of the Tunguska Cosmic Body. Seismic-reflection and magnetic data revealed a P-wave velocity/magnetic anomaly close to the lake center, about 10 m below the lake floor; this anomaly is compatible with the presence of a buried stony object and supports the impact crater origin for Lake Cheko.350 33