467 research outputs found

    Geometric and Kinematic modeling of the thrust fronts in the Montello-Cansiglio area from geologic and geodetic data (Eastern Southalpine Chain, NE Italy)

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    Questo lavoro è dedicato allo studio delle geometrie e dei ratei di deformazione di breve e medio termine delle strutture compressive attive facenti parte dei fronti esterni della Catena Sudalpina, nel settore dell’anticlinale del Montello. Il metodo adottato utilizza informazioni derivate dall’analisi di una linea geodetica di primo ordine dell’IGM, combinate con osservazioni geofisiche, geologiche e geomorfologiche di superficie e di sottosuolo. La linea geodetica presa in esame mostra lungo alcuni suoi segmenti dei movimenti verticali relativi, positivi rispetto ai segmenti adiacenti (maggiori sollevamenti). Questi segnali geodetici, ottenuti dal confronto delle quote dei capisaldi misurate durante due distinte campagne separate da un intervallo di tempo di circa 50 anni, avvengono in corripondenza dell’attraversamento di faglie cieche e sono stati quindi interpretati come dovuti all’attività di queste strutture sepolte. Per l’interpretazione, è stata costruita una sezione geologica che segue la traccia della linea di livellazione, ed è stato quindi modelizzato il segnale geodetico adottando un metodo diretto. Nel modello, le geometrie di partenza delle faglie sono state prese dalla sezione geologica, e sono state poi modificate per riprodurre il segnale geodetico. Una volta fissate le geometrie delle faglie, gli uplift rate sono stati convertiti in slip e shortening rate e comparati con: 1- i ratei di medio e lungo termine derivati dalle osservazioni geologiche e geomorfologiche per evidenziare eventuali cambiamenti nel tempo; e 2- con i tassi di convergenza GPS per studiare la partizione delle deformazione tra i diversi fronti. Infine sono state usate relazioni analitiche ed empiriche per stimare la massima magnitudo e i tempi di ricorrenza dei potenziali futuri terremoti

    Discovering the characteristics of the surface faulting ancestors of the L’Aquila April 6, 2009 earthquake by paleoseismological investigations

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    The occurrence of the Mw 6.3, April 6, 2009 earthquake has highlighted how critical is the development of hazard models that incorporate all the information on the long-term seismic behavior of faults (i.e., individual events rupture length and slip, timing, etc.). Under this light we started a campaign of paleoseismological investigations in the epicentral area. The 2009 earthquake occurred on the Paganica normal fault (PF hereinafter) and produced a max 0.15 m high, 3 km-long continuous surface rupture along its central section, as well as several short, discontinuous cracks along the rest of the fault trace; secondary slip along nearby tectonic structures was observed too. The PF consists of a prominent NW-SE striking and SW dipping long-term morphologic scarp formed by the tectonic juxtaposition of Pliocene-middle Pleistocene and late Pleistocene alluvial deposits, and by smaller compound scarps in late Pleistocene-Holocene deposits. The fault runs for a total length of about 20 km along the NE side of the Aterno River valley, a graben-type basin bounded by marked antithetic faults. The limited extent and the small throw of the 2009 surface ruptures, when compared to the size of the Paganica long-term fault scarp, raise questions about the evolution and rupture history of this fault and suggest that the PF may have experienced larger Magnitude earthquakes than the 2009 seismic event. With the aim of defining the Max Magnitude expected for the PF by determining the size of the individual coseismic surface ruptures occurred in the past and their max extent, their frequency and the average rate of displacement we have been excavating new trenches and studied artificial exposures across the PF fault zone, in most of the cases intersecting the 2009 surface ruptures. Preliminary results show evidence for repeated decimetric surface faulting events during the past 3 millennia with the penultimate likely being the 1461 event (Me 6.4); evidence for possible previous larger slip events is found too. Whether the small ruptures are all related to slip at depth on the PF or would represent sympathetic slip triggered by earthquake occurred on nearby faults should be better investigated. Conversely, provided the “double size” slip behavior of the PF is confirmed, to characterize the seismic hazard of the area we should consider a more complex seismogenic model than that presently applied. In particular, we should include also the scenario that the PF produces relatively frequent (each 4-600 yr) 2009-type earthquakes and rare (each 3-4 millennia) larger events, likely in connection with other nearby active structures (i.e., San Demetrio Fault? Pettino Fault?)

    Looking for seismites in the Fucino basin: preliminary results from a combined geological geophysical approach.

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    We present a combined geological-geophysical study on the lacustrine sequence of the Fucino Plain (central Italy). New acquired data on liquefaction features and the recovery of a seismite in the lacustrine sequence are shown. Our preliminary results suggest the occurrence of three seismic events in the last ca. 45 kyr. Moreover, a first attempt to find out the source deposit responsible of the widespread liquefaction phenomena has been performed by means of shallow engine boreholes and ERT profiles

    Imaging the three-dimensional architecture of the Middle Aterno basin (2009 L’Aquila earthquake, Central Italy) using ground TDEM and seismic noise surveys: preliminary results

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    We present preliminary results from a multidisciplinary geophysical approach applied to the imaging of the threedimensional architecture of the Middle Aterno basin, close to the epicentral area of the 2009 L’Aquila earthquake (central Italy). We collected several time domain electromagnetic soundings (TDEM) coupled with seismic noise measurements focusing on the characterization of the bedrock/infill interface. Our preliminary results agree with existing geophysical data collected in the area, and show that the southeastern portion of the basin is characterized by a deepening of the Mesozoic-Tertiary bedrock down to a depth of more than 450 m. We found that a joint use of electromagnetic and seismic methods significantly contributes in obtaining new insights on the 3D geometry of the Middle Aterno basin. Moreover, we believe that our combined approach based on TDEM and noise measurements can be adopted to investigate similar geological settings elsewhere.PublishedPescina (AQ)2T. Tettonica attivaope

    Imaging the three-dimensional architecture of the Middle Aterno basin (2009 L’ Aquila earthquake, Central Italy) using ground TDEM and seismic noise surveys: preliminary results

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    We present preliminary results from a multidisciplinary geophysical approach ap- plied to the imaging of the three-dimensional architecture of the Middle Aterno basin, close to the epicentral area of the 2009 L’Aquila earthquake (central Italy). We collected several time domain electromagnetic soundings (TDEM) coupled with seismic noise measurements focu- sing on the characterization of the bedrock/in ll interface. Our preliminary results agree with existing geophysical data collected in the area, and show that the southeastern portion of the basin is characterized by a deepening of the Mesozoic-Tertiary bedrock down to a depth of more than 450 m. We found that a joint use of electromagnetic and seismic methods signi - cantly contributes in obtaining new insights on the 3D geometry of the Middle Aterno basin. Moreover, we believe that our combined approach based on TDEM and noise measurements can be adopted to investigate similar geological settings elsewhere.PublishedPescina (AQ), Italy2T. Tettonica attiva3T. Pericolosità sismica e contributo alla definizione del rischio7A. Geofisica di esplorazioneope

    Imaging the three-dimensional architecture of the Middle Aterno basin (2009 L’Aquila earthquake, Central Italy) using ground TDEM and seismic noise surveys: preliminary results

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    We present preliminary results from a multidisciplinary geophysical approach applied to the imaging of the threedimensional architecture of the Middle Aterno basin, close to the epicentral area of the 2009 L’Aquila earthquake (central Italy). We collected several time domain electromagnetic soundings (TDEM) coupled with seismic noise measurements focusing on the characterization of the bedrock/infill interface. Our preliminary results agree with existing geophysical data collected in the area, and show that the southeastern portion of the basin is characterized by a deepening of the Mesozoic-Tertiary bedrock down to a depth of more than 450 m. We found that a joint use of electromagnetic and seismic methods significantly contributes in obtaining new insights on the 3D geometry of the Middle Aterno basin. Moreover, we believe that our combined approach based on TDEM and noise measurements can be adopted to investigate similar geological settings elsewhere

    EXTL3 mutations cause skeletal dysplasia, immune deficiency, and developmental delay.

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    We studied three patients with severe skeletal dysplasia, T cell immunodeficiency, and developmental delay. Whole-exome sequencing revealed homozygous missense mutations affecting exostosin-like 3 (EXTL3), a glycosyltransferase involved in heparan sulfate (HS) biosynthesis. Patient-derived fibroblasts showed abnormal HS composition and altered fibroblast growth factor 2 signaling, which was rescued by overexpression of wild-type EXTL3 cDNA. Interleukin-2-mediated STAT5 phosphorylation in patients' lymphocytes was markedly reduced. Interbreeding of the extl3-mutant zebrafish (box) with Tg(rag2:green fluorescent protein) transgenic zebrafish revealed defective thymopoiesis, which was rescued by injection of wild-type human EXTL3 RNA. Targeted differentiation of patient-derived induced pluripotent stem cells showed a reduced expansion of lymphohematopoietic progenitor cells and defects of thymic epithelial progenitor cell differentiation. These data identify EXTL3 mutations as a novel cause of severe immune deficiency with skeletal dysplasia and developmental delay and underline a crucial role of HS in thymopoiesis and skeletal and brain development

    Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

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    Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

    Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

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    A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters
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