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  • 1
    Publication Date: 2013-07-05
    Description: The accurate definition of 3-D crustal structures and, in primis, the Moho depth, are the most important requirement for seismological, geophysical and geodynamic modelling in complex tectonic regions. In such areas, like the Mediterranean region, various active and passive seismic experiments are performed, locally reveal information on Moho depth, average and gradient crustal V p velocity and average V p / V s velocity ratios. Until now, the most reliable information on crustal structures stems from controlled-source seismology experiments. In most parts of the Alpine region, a relatively large number of controlled-source seismology information are available though the overall coverage in the central Mediterranean area is still sparse due to high costs of such experiments. Thus, results from other seismic methodologies, such as local earthquake tomography, receiver functions and ambient noise tomography can be used to complement the controlled-source seismology information to increase coverage and thus the quality of 3-D crustal models. In this paper, we introduce a methodology to directly combine controlled-source seismology and receiver functions information relying on the strengths of each method and in relation to quantitative uncertainty estimates for all data to derive a well resolved Moho map for Italy. To obtain a homogeneous elaboration of controlled-source seismology and receiver functions results, we introduce a new classification/weighting scheme based on uncertainty assessment for receiver functions data. In order to tune the receiver functions information quality, we compare local receiver functions Moho depths and uncertainties with a recently derived well-resolved local earthquake tomography-derived Moho map and with controlled-source seismology information. We find an excellent correlation in the Moho information obtained by these three methodologies in Italy. In the final step, we interpolate the controlled-source seismology and receiver functions information to derive the map of Moho topography in Italy and surrounding regions. Our results show high-frequency undulation in the Moho topography of three different Moho interfaces, the European, the Adriatic–Ionian, and the Liguria–Corsica–Sardinia–Tyrrhenia, reflecting the complexity of geodynamical evolution.
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 2
    Publication Date: 2012-11-07
    Description: To further characterize the genetic basis of primary biliary cirrhosis (PBC), we genotyped 2426 PBC patients and 5731 unaffected controls from three independent cohorts using a single nucleotide polymorphism (SNP) array (Immunochip) enriched for autoimmune disease risk loci. Meta-analysis of the genotype data sets identified a novel disease-associated locus near the TNFSF11 gene at 13q14, provided evidence for association at six additional immune-related loci not previously implicated in PBC and confirmed associations at 19 of 22 established risk loci. Results of conditional analyses also provided evidence for multiple independent association signals at four risk loci, with haplotype analyses suggesting independent SNP effects at the 2q32 and 16p13 loci, but complex haplotype driven effects at the 3q25 and 6p21 loci. By imputing classical HLA alleles from this data set, four class II alleles independently contributing to the association signal from this region were identified. Imputation of genotypes at the non- HLA loci also provided additional associations, but none with stronger effects than the genotyped variants. An epistatic interaction between the IL12RB2 risk locus at 1p31and the IRF5 risk locus at 7q32 was also identified and suggests a complementary effect of these loci in predisposing to disease. These data expand the repertoire of genes with potential roles in PBC pathogenesis that need to be explored by follow-up biological studies.
    Print ISSN: 0964-6906
    Electronic ISSN: 1460-2083
    Topics: Biology , Medicine
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  • 3
    Publication Date: 2020-10-26
    Description: In complex tectonics regions, seismological, geophysical, and geodynamic modeling require accurate definition of the Moho geometry. Various active and passive seismic experiments performed in the central Mediterranean region revealed local information on the Moho depth, in some cases used to produce interpolated maps. In this paper, we present a new and original map of the 3-D Moho geometry obtained by integrating selected high-quality controlled source seismic and teleseismic receiver function data. The very small cell size makes the retrieved model suitable for detailed regional studies, crustal corrections in teleseismic tomography, advanced 3-D ray tracing in regional earthquake location, and local earthquake tomography. Our results show the geometry of three different Moho interfaces: the European, Adriatic-Ionian, and Tyrrhenian. The three distinct Moho are fashioned following the Alpine and Apennines subduction, collision, and back-arc spreading and show medium- to high-frequency topographic undulations reflecting the complexity of the geodynamic evolution.
    Description: Published
    Description: Q09006
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: Italy; controlled source seismology; crust; receiver function ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
    Publication Date: 2017-04-04
    Description: The Colli Albani is a Quaternary quiescent volcano, located a few kilometers southeast of Rome (Italy). During the past decade, seismic swarms, ground deformation, and gas emissions occurred in the southwestern part of the volcano, where the last phreatomagmatic eruptions (27 ka) developed, building up several coalescent craters. In the frame of a Dipartimento Protezione Civile – Istituto Nazionale di Geofisica e Vulcanologica project aimed at the definition and mitigation of volcanic hazard, a temporary array of seismic stations has been deployed on the volcano and surrounding areas. We present results obtained using receiver functions analysis for eight stations, located upon and around the volcanic edifice, and revealing how the built of the volcanic edifice influenced the prevolcanic structures. The stations show some common features: the Moho is almost flat and located at 23 km, in agreement with the thinning of the Thyrrenian crust. Also the presence of a shallow limestone layer is a stable feature under every station, with a variable thickness between 4 and 5 km. However, some features change from station to station, indicating a local complexity of the crustal structure: a shallow discontinuity dividing the Plio-Pleistocene sediments by the Meso-Cenozoic limestones, and a localized anisotropic layer, in the central part of the old structure, which points of the deformation of the limestones. Other two strongly anisotropic layers are detected under the stations in lower crust and upper mantle, with symmetry axis directions related to the evolution of the volcano complex.
    Description: Published
    Description: B09313
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: Receiver Function ; Colli Albani ; crustal structure ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
    Publication Date: 2017-04-04
    Description: Receiver functions (RFs) analyzed at two permanent broadband seismic stations operating in the epicentral area of theMw 6.3, 2009 L’Aquila earthquake (central Italy) yield insight on crustal structure along the fault rupture. The harmonic decomposition of RFs highlights a subsurface structure in which both isotropic and anisotropic features are present. We model the waveforms using recently developed Monte Carlo methods. The retrieved models display a common depth structure, between 10 and 40 km depth, consistent with the under‐thrusting of the Adria lithosphere underneath the Apennines belt. Along the fault, in the uppermost crust, the S wave velocity structure is laterally heterogeneous. Right above the hypocenter, we find a 4–6 km thick, very high S wave velocity body (Vs as high as 4.2 km/s) that is absent in the SE portion of the fault, where the earthquake propagated. The high‐Vs body is coincident with the area of fewer aftershocks and is anticorrelated with the maximum slip patches of the earthquake, as modeled by differential interferometric synthetic aperture radar (DInSAR) and strong motion data. We interpret this high‐Vs body as a high‐strength barrier responsible for the high peak ground motion in the near field, observed in the L’Aquila city and surroundings, and for the complexity in the rupture evolution. The retrieved seismic S wave velocity of this body far exceeds common Vs values in the upper crust and it is more compatible with values observed in mafic basement rocks.
    Description: Published
    Description: B12326
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: L'Aquila earthquake ; receiver function ; S-velocity model ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 6
    Publication Date: 2017-04-04
    Description: Il 23 dicembre 2008 un terremoto di magnitudo (ML) 5.2 ha interessato l’area pede-appenninica fra le provincie di Reggio Emilia e Parma. L’evento sismico, avvertito da gran parte della popolazione dell’Italia centro-settentrionale, è stato localizzato dall’Istituto Nazionale di Geofisica e Vulcanologia (INGV) ad una profondità ipocentrale di circa 23 km tra i comuni di Vetto, Canossa e Neviano degli Arduini (Lat. 44.544N e Lon. 10.345E). La scossa principale è stata preceduta di 6 minuti da un evento di ML 3.4 e seguita nelle ore e nei giorni successivi da numerose repliche alcune delle quali hanno superato la soglia di magnitudo 31. A parte il comprensibile effetto sulla popolazione, che dopo l'evento sismico si è in molti casi riversata nelle strade, sono stati registrati danni moderati distribuiti in una zona piuttosto ampia delle provincie di Parma, Reggio Emilia e Modena. Il rilievo diretto degli effetti macrosismici effettuato dal gruppo QUEST2 nei giorni immediatamente successivi all'evento "ha evidenziato situazioni di danneggiamento sporadico, distribuito su un’area abbastanza ampia. Si tratta in genere di caduta di comignoli, slittamento di tegole, crepe sui muri, talvolta passanti, e fessurazioni negli intonaci. Raramente crollo di vecchie murature. Prevalentemente il danneggiamento è limitato all’edilizia monumentale (chiese, castelli, palazzi comunali, ecc.) e a situazioni di generale degrado preesistente, sia sull’edilizia monumentale stessa (in particolare numerose chiese di campagna, utilizzate di rado) che su quella ad uso abitativo” [Ercolani et al., 2009]. A poche ore dal mainshock personale afferente alla Rete Sismica Mobile (RSM) del Centro Nazionale Terremoti (CNT), in sinergia con i colleghi della Sezione Milano–Pavia, ha installato alcune stazioni sismiche ad integrazione della Rete Sismica Nazionale (RSN) dell’INGV già presente nell’area con l’obiettivo di acquisire dati di maggiore qualità e dettaglio in modo tale da poter studiare le sorgenti sismiche, l’evoluzione spazio-temporale della sequenza e caratterizzare attraverso la micro sismicità, le strutture di faglia attivate. L’acquisizione del segnale sismico è continuata per circa 2 mesi fornendo dati in continuo per circa 15Gb. Tale dataset è oggi disponibile integrato nel sistema di archiviazione e gestione dei dati prodotti dalla RSN dell’INGV [Moretti et al., 2010c] e distribuito nel formato standard internazionale SEED (Standard for the Exchange of Earthquake Data) attraverso il portale EIDA3. In questo lavoro, dopo una breve descrizione sismologica dell’area, vengono presentati i dettagli tecnici dell’intervento e le specifiche relative all’archiviazione e distribuzione dei dati.
    Description: Istituto Nazionale di Geofisica e Vulcanologia
    Description: Published
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: open
    Keywords: Seismic Monitoring ; Emergency ; Waveform archive ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: report
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  • 7
    Publication Date: 2017-04-04
    Description: We present a new P wave and S wave velocity model for the upper crust beneath Long Valley Caldera obtained using local earthquake tomography and receiver function analysis. We computed the tomographic model using both a graded inversion scheme and a traditional approach. We complement the tomographic Vp model with a teleseismic receiver function model based on data from broadband seismic stations (MLAC and MKV) located on the SE and SW margins of the resurgent dome inside the caldera. The inversions resolve (1) a shallow, high‐velocity P wave anomaly associated with the structural uplift of a resurgent dome; (2) an elongated, WNW striking low‐velocity anomaly (8%–10 % reduction in Vp) at a depth of 6 km (4 km below mean sea level) beneath the southern section of the resurgent dome; and (3) a broad, low‐velocity volume (∼5% reduction in Vp and as much as 40% reduction in Vs) in the depth interval 8–14 km (6–12 km below mean sea level) beneath the central section of the caldera. The two low‐velocity volumes partially overlap the geodetically inferred inflation sources that drove uplift of the resurgent dome associated with caldera unrest between 1980 and 2000, and they likely reflect the ascent path for magma or magmatic fluids into the upper crust beneath the caldera.
    Description: Published
    Description: B12314
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: Seismic Tomography ; Long Valley Caldera ; Receiver Function ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 8
    Publication Date: 2020-02-24
    Description: The crustal structure of central Apennines (Italy) is still poorly defined, leaving uncertainties on the tectonic style (thin or thick-skinned) responsible for the development of the thrust-and-fold belt. The today active extension, which replaced compression since early Quaternary, is presumably in"uenced by the pre-existing structure that yields location and segmentation of the fault system. To focus on such issues, we computed P and S-wave velocity models of the crust by using the independent methodologies of local earthquakes tomography and teleseismic receiver function. We document strong lateral and vertical heterogeneities that define shallow, imbricate sheets of the Mesozoic cover that overlay exceptionally high Vp and high Vs bodies. These bodies can be interpreted as either dolomitic or, partially hydrated, ma!c rocks. The two alternative interpretations respectively imply an ultra-thick deposition of dolomitic rocks in the hanging wall of Triassic normal fault or a deep exhumation of the Pre-Mesozoic basement during the early Mesozoic sin-rift tectonic. In both cases, these bodies in"uenced the evolution of the thrust-and-fold belt. Very remarkably, active normal faults, like those ruptured during the still ongoing 2009 L'Aquila sequence, concentrate at the border of these bodies, suggesting that they have an active role in the segmentation of the normal fault system. The rheological behavior of such high Vp high Vs bodies, weak or strong, is still uncertain, but of utmost importance to understand the risk of future normal faulting earthquakes.
    Description: Published
    Description: 462-476
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: Abruzzo ; tomography ; receiver functions ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 9
    Publication Date: 2017-04-03
    Description: Subduction zones are the place in the world where fluids are transported from the foredeep to the mantle and back-to-the-surface in the back-arc. The subduction of an oceanic plate implies the transportation of the oceanic crust to depth and its methamorphization. Oceanic sediments release water in the (relatively) shallower part of the subduction zone, while dehydration of the subducted basaltic crust allows fluid circulation at larger depths. While the water budget in oceanic subduction has been deeply investigated, less attention has been given to the fluids implied in the subduction of a continental margin (i.e. in continental subduction). In this study, we use teleseismic receiver function (RF) analysis to image the process of water migration at depth, from the subducting plate to the mantle wedge, under the Northern Apennines (NAP, Italy). Harmonic decomposition of the RF data-set is used to constrain both isotropic and anisotropic structures. Isotropic structures highlight the subduction of the Adriatic lower crust under the NAP orogens, from 35–40 km to 65 km depth, as a dipping low S-velocity layer. Anisotropic structures indicate the presence of a broad anisotropic zone (anisotropy as high as 7%). This zone develops in the subducted Adriatic lower crust and mantle wedge, between 45 and 65 km depth, directly beneath the orogens and the more recent back-arc extensional basin. The anisotropy is related to the metamorphism of the Adriatic lower crust (gabbro to blueschists) and its consequent eclogitization (blueschists to eclogite). The second metamorphic phase releases water directly in the mantle wedge, hydrating the back-arc upper mantle. The fluid migration process imaged in this study below the northern Apennines could be a proxy for understanding other regions of ongoing continental subduction.
    Description: Published
    Description: 267–278
    Description: JCR Journal
    Description: restricted
    Keywords: fluid migration; seismic anisotropy; Northern Apennines; receiver function ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 10
    Publication Date: 2017-05-23
    Description: A MW 6.3 earthquake struck on April 6, 2009 the Abruzzi region (central Italy) producing vast damage in the L’Aquila town and surroundings. In this paper we present the location and geometry of the fault system as obtained by the analysis of main shock and aftershocks recorded by permanent and temporary networks. The distribution of aftershocks, 712 selected events with ML 2.3 and 20 with ML 4.0, defines a complex, 40 km long, NW trending extensional structure. The main shock fault segment extends for 15–18 km and dips at 45 to theSW, between 10 and 2 km depth. The extent of aftershocks coincides with the surface trace of the Paganica fault, a poorly known normal fault that, after the event, has been quoted to accommodate the extension of the area.We observe a migration of seismicity to the north on an echelon fault that can rupture in future large earthquakes.
    Description: Published
    Description: L18308
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: reserved
    Keywords: seismic sequence ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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