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  • 1
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    Shallow slip amplification and enhanced tsunami hazard unravelled by dynamic simulations of mega-thrust earthquakes (2018)
    Details
    Publikationsdatum: 2021-02-10
    Beschreibung: The 2011 Tohoku earthquake produced an unexpected large amount of shallow slip greatly contributing to the ensuing tsunami. How frequent are such events? How can they be efficiently modelled for tsunami hazard? Stochastic slip models, which can be computed rapidly, are used to explore the natural slip variability; however, they generally do not deal specifically with shallow slip features. We study the systematic depth-dependence of slip along a thrust fault with a number of 2D dynamic simulations using stochastic shear stress distributions and a geometry based on the cross section of the Tohoku fault. We obtain a probability density for the slip distribution, which varies both with depth, earthquake size and whether the rupture breaks the surface. We propose a method to modify stochastic slip distributions according to this dynamically-derived probability distribution. This method may be efficiently applied to produce large numbers of heterogeneous slip distributions for probabilistic tsunami hazard analysis. Using numerous M9 earthquake scenarios, we demonstrate that incorporating the dynamically-derived probability distribution does enhance the conditional probability of exceedance of maximum estimated tsunami wave heights along the Japanese coast. This technique for integrating dynamic features in stochastic models can be extended to any subduction zone and faulting style.
    Beschreibung: Published
    Beschreibung: 35007
    Beschreibung: 2T. Sorgente Sismica
    Beschreibung: 5T. Modelli di pericolosità sismica e da maremoto
    Beschreibung: JCR Journal
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 2
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    Enabling FAIR research in Earth Science through research objects (2019)
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    Publikationsdatum: 2021-03-16
    Beschreibung: Data-intensive science communities are progressively adopting FAIR practices that enhance the visibility of scientific breakthroughs and enable reuse. At the core of this movement, research objects contain and describe scientific information and resources in a way compliant with the FAIR principles and sustain the development of key infrastructure and tools. This paper provides an account of the challenges, experiences and solutions involved in the adoption of FAIR around research objects over several Earth Science disciplines. During this journey, our work has been comprehensive, with outcomes including: an extended research object model adapted to the needs of earth scientists; the provisioning of digital object identifiers (DOI) to enable persistent identification and to give due credit to authors; the generation of content-based, semantically rich, research object metadata through natural language processing, enhancing visibility and reuse through recommendation systems and third-party search engines; and various types of checklists that provide a compact representation of research object quality as a key enabler of scientific reuse. All these results have been integrated in ROHub, a platform that provides research object management functionality to a wealth of applications and interfaces across different scientific communities. To monitor and quantify the community uptake of research objects, we have defined indicators and obtained measures via ROHub that are also discussed herein.
    Beschreibung: Published
    Beschreibung: 550-564
    Beschreibung: 5IT. Osservazioni satellitari
    Beschreibung: JCR Journal
    Schlagwort(e): earth science ; research objects ; FAIR principles ; Semantic technologies ; 05.01. Computational geophysics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 3
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    Editorial: The Impact of Open Science for Evaluation of Volcanic Hazards (2021)
    Frontiers
    Details
    Publikationsdatum: 2021-06-09
    Beschreibung: The Open Science paradigm addresses the scientific process of producing and sharing knowledge and data as early as possible in the research development, through digital and collaborative technology. It includes findable and interoperable data, access to data processing platforms, and sharing of research products within the scientific community and with stakeholders. Open Science increases the quality and impact of science by fostering reproducibility and interdisciplinarity.
    Beschreibung: Published
    Beschreibung: 659772
    Beschreibung: 5V. Processi eruttivi e post-eruttivi
    Beschreibung: JCR Journal
    Schlagwort(e): volcanic hazards and risk ; remote sensing ; natural hazards ; open science ; findable accessible interoperable and reusable principles ; database (all types) ; volcanic unrest ; eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 4
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    Source modelling from ground deformation and gravity changes at Campi Flegrei caldera (2021)
    Springer
    Details
    Publikationsdatum: 2021-06-10
    Beschreibung: The deformation history of the Campi Flegrei caldera during the last decades consists of two large uplift events in 1970-72 and 1982-84, with ~ 3.5 m cumula-tive uplift, occurring at a rate of ~ 1 m/yr. Both events were accompanied by seismic activity, gravity changes and compositional variations of volcanic gasesbut no eruption took place. During the following decades,the area has been slowly subsiding but minor uplift episodes (~ a few cm), seismic swarms and changes in degassing activitytook place, showing that the area persistedin a near-critical state.Since 2004, ground deformation resumed, although at a slower rate, totaling a displacement of ~ 0.6 m at the time we write(2019). In this chapter,we present a retrospective analysis of ground deformationleading to acritical re-evaluationof the 1982-84 uplift and of the following deflation, employing the most updated modeling techniques. Deformation and gravity data provide important constraints on depth, volume, mass density and dislocation mechanisms accompanying mag-ma emplacement processes but the correct evaluation of these parameters is strongly conditioned by simplifying assumptions built in the different inversion procedures: in particular, the inferred depth ranges from 5.5 km to less than 3 km and the intrusion density ranges from values pertinent to aqueous fluids to typical magmatic values. This review depicts the salient phases of the deformationhistory of this densely populated and high risk volcanic area, helping to address debated issues, such as the role of the magmatic system, and theirinteraction with the shal-lower hydrothermal system.In spite of the mentioned difficulties, the following conclusion may be considered as firmly established: during 1982-84 a magmatic intrusion took place, and the subsequent complex deformation history (1985-2010) was mainly controlled by the exsolution of volatiles withmagmatic origin and their interaction with a shallow hydrothermal system. However, data collected af-ter 2011 were modelled in terms of a deeperinflating source of deformation, pos-sibly resulting froma resumed magmatic recharge at depth.
    Beschreibung: Submitted
    Beschreibung: 4V. Processi pre-eruttivi
    Schlagwort(e): Campi Flegrei ; volcanoes
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: book chapter
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  • 5
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    FEM inversion of DInSAR data of the 2009 L’Aquila Earthquake (Italy) (2011)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Slip distribution on fault planes is usually retrieved by geodetic data assuming the local crust as an elastic, homogeneous and isotropic half-space. However, realistic complexities such as non-homogeneous elastic structure and topographic relief can be handled only by numerical methods. Such elaborated models are computationally expensive and are usually implemented for forward modelling rather than for inversion purposes. On the other hand, spatially dense geodetic data (e.g. DInSAR displacement maps) often reveal complex patterns of coseismic deformation, pointing out the oversimplification of the analytical models. We develop a procedure to perform inversion of geodetic data based on Finite Element (FE) method, accounting for a more realistic description of the Earth crust, e.g. medium heterogeneity, anisotropy, topographic relief. FE computed Green functions are implemented in an inversion framework to constrain the fault slip distribution in complex media. The method is applied to the 2009 L’Aquila earthquake (Mw 6.3). The fault geometry is constrained by three DInSAR maps of coseismic displacement from ENVISAT and COSMO-Skymed satellites. In addition to these re-computed images, we use near-field GPS data. The fault dip is fixed at 50°, in accordance to recently relocated aftershocks of the L’Aquila earthquake. We build a FE model including the fault geometry previously determined and the heterogeneities of the local crust. A linear inversion is performed to constrain the slip distribution in the heterogeneous medium. Results from inversions highlight the non-negligible influence of the medium structure: homogeneous and heterogeneous models show discrepancies in the fault slip distribution values up to 20%.
    Beschreibung: Published
    Beschreibung: Wien
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: open
    Schlagwort(e): earthquake ; finite element
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Oral presentation
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  • 6
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    The Mw 7.9Wenchuan (China) Earthquake: exploring the role of crustal heterogeneities from finite element analysis of DInSAR coseismic deformation (2011)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: A destructive (Mw 7.9) earthquake struck the Sichuan province (China) on May 12, 2008. The seismic event, the largest in China in more than three decades and referred as the Wenchuan earthquake, ruptured approximately 280 km of the Yingxiu-Beichuan fault and about 70 km of the Guanxian-Anxian fault. Surface effects were suffered over a wide epicentral area (about 300 km E-W and 250 km N-S). The huge earthquake took place within the context of long term uplift of the Longmen Shan range in eastern Tibet. The Longmen Shan fault zone is the main tectonic boundary between the Sichuan basin and eastern Tibet and is characterized by a large topographic relief (from 500m a.s.l. to more than 4000m) and large variations in rheological properties. The coseismic deformation is imaged by a set of ALOS-PALSAR L-band SAR interferograms. We use an unprecedented high number of data (25 frames from 6 adjacent tracks) to encompass the entire coseismic area. The resulting mosaic of differential interferograms covers an overall area of about 340 km E-W and 240 km N-S. The complex geophysical context of Longmen Shan and the variations of the fault geometry along its length can be better handled by means of numerical methods. The fault geometry is constrained by inversions of geodetic data and by taking into account the geological features of eastern Tibet and Sichuan basin. As a result, we build a Finite Element (FE) model consisting of two non planar faults embedded in a non-homogeneous medium with real topography of the area. We develop a procedure to perform inversions of DInSAR data based on FE computed Green functions of the surface displacement field. We retrieve a complex slip distribution on the fault segments in a heterogeneous medium with realistic surface topography.
    Beschreibung: Published
    Beschreibung: Wien
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: open
    Schlagwort(e): earthquake ; finite element ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Conference paper
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  • 7
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    Geometrical and physical properties of the 1982-84 deformation source at Campi Flegrei - Italy (2011)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Deformation of the ground surface in volcanic areas is generally recognized as a reliable indicator of unrest, possibly resulting from the intrusion of fresh magma within the shallow rock layers. The intrusion process is usually represented by a deformation source such as an ellipsoidal pressurized cavity, embedded within a homogeneous and elastic half-space. Similar source models allow inferring the depth, the location and the (incremental) volume of the intrusion, which are very important parameters for volcanic risk implications. However, assuming a homogeneous and elastic rheology and, assigning a priori the shape and the mechanism of the source (within a very restricted “library” of available solutions) may bias considerably the inference of source parameters. In complete generality, any point source deformation, including overpressure sources, may be described in terms of a suitable moment tensor, while the assumption of an overpressure source strongly restricts the variety of allowable moment tensors. In particular, by assuming a pressurized cavity, we rule out the possibility that either shear failure may precede magma emplacement (seismically induced intrusion) or may accompany it (mixed tensile and shear mode fracture). Another possibility is that a pre-existent weakness plane may be chosen by the ascending magma (fracture toughness heterogeneity). We perform joint inversion of levelling and EDM data (part of latter are unpublished), collected during the 1982-84 unrest at Campi Flegrei caldera: a 43% misfit reduction is obtained for a general moment source if the elastic heterogeneities computed from seismic tomography are accouted for. The inferred source is at 5.2 km depth but cannot be interpreted as a simple pressurized cavity. Moreover, if mass conservation is accounted for, magma emplaced within a shallow source must come from a (generally deeper) reservoir, which is usually assumed to be deep enough to be simply neglected. At Campi Flegrei, seismic tomography indicates that the “deep” magma source is rather shallow (at 7-8 km depth), so that its presence should be included in any thorough attempt to source modeling. Taking into account a deflating source at 7.5 km depth (represented either as a horizontal sill or as an isotropic cavity) and an inflating moment source, the fit of both levelling and EDM data improves further (misfit reduction 80%), but still the best fitting moment source (at 5.5 km depth) falls outside the range of pressurized ellipsoidal cavities. The shallow moment source may be decomposed in a tensile and a shear dislocation. No clue is obtained that the shear and the tensile mechanisms should be located in different positions. Our favourite interpretation is in terms of a crack opening in mixed tensile and shear mode, as would be provided by fluid magma unwelding pre-stressed solid rock. Although this decomposition of the source is not unique, the proposed solution is physically motivated by the minimum overpressure requirement. An important implication of this new interpretation is that the magma emplaced in the shallow moment source during the 1982-84 unrest was not added to already resident magma at the same position.
    Beschreibung: Published
    Beschreibung: Wien
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: open
    Schlagwort(e): volcanic source ; elastic structure ; unrest ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Conference paper
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  • 8
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    Magma Degassing as a Source of Long‐Term Seismicity at Volcanoes: The Ischia Island (Italy) Case (2020)
    Details
    Publikationsdatum: 2020-02-05
    Beschreibung: Transient seismicity at active volcanoes poses a significant risk in addition to eruptive activity. This risk is powered by the common belief that volcanic seismicity cannot be forecast, even on a long term. Here we investigate the nature of volcanic seismicity to try to improve our forecasting capacity. To this aim, we consider Ischia volcano (Italy), which suffered similar earthquakes along its uplifted resurgent block. We show that this seismicity marks an acceleration of decades‐long subsidence of the resurgent block, driven by degassing of magma that previously produced the uplift, a process not observed at other volcanoes. Degassing will continue for hundreds to thousands of years, causing protracted seismicity and will likely be accompanied by moderate and damaging earthquakes. The possibility to constrain the future duration of seismicity at Ischia indicates that our capacity to forecast earthquakes might be enhanced when seismic activity results from long‐term magmatic processes, such as degassing.
    Beschreibung: Published
    Beschreibung: 14421-14429
    Beschreibung: 2V. Struttura e sistema di alimentazione dei vulcani
    Beschreibung: JCR Journal
    Schlagwort(e): degassing ; geodetic data ; modelling ; ischia ; 04.08. Volcanology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 9
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    Synergic Use of Multi-Sensor Satellite Data for Volcanic Hazards Monitoring: The Fogo (Cape Verde) 2014–2015 Effusive Eruption (2020)
    Frontiers Media
    Details
    Publikationsdatum: 2020-05-29
    Beschreibung: Monitoring volcanic eruptions provides key information for hazard assessment and its time evolution. Satellite remote sensing data are nowadays essential to perform such task, thanks to their capability to survey disastrous events also in remote and under-monitored regions, with frequent revisit time and accurate spatial resolution. Even though satellite imageries are presently used to analyze several phenomena related to eruptions, automatic methods and synergic exploitation of different sensors are rarely considered. In this work, we have analyzed satellite images coming from both synthetic apertureradar(SAR)andopticalsensors,tostudytheeffusiveeruptionofFogovolcano, CapeVerde,whichtookplacebetweenNovember2014andJanuary2015.Inparticular, we have exploited multi-sensor images from Sentinel-1, COSMO-SkyMed, Landsat8, and Earth-Observing-1 missions, to retrieve lava flow patterns and volcanic source parameters related to the eruption. The main outcome of our work is the application of a new automatic change detection technique for estimating the lava field and its temporalevolution,combiningtheSARintensityandtheinterferometricSARcoherence. The innovative algorithm is able to take full advantage of the Sentinel-1 mission’s 6day repeat cycle. Such data are here used for the first time for lava mapping, thereby providing an unprecedented example of using the multi-temporal interferometric SAR (InSAR) coherence to automatically monitor lava flow evolution in emergency phase. This new technique, jointly used with optical satellite images, is capable of resolving with spatial and temporal detail the evolution of lava flows. We have also performed differential SAR interferometry (DInSAR) to map the ground deformation and retrieve the feeding dyke by inverting syn-eruptive signals. Results from source modeling show a SW-NE oriented dyke, located inside Chã das Caldeiras, SW of the Pico do Fogo. Our work highlights how multidisciplinary and satellite open data, along with innovative and automatic processing techniques, may be adopted for real-time hazard estimates in an operational environment
    Beschreibung: Published
    Beschreibung: Article 22
    Beschreibung: 1V. Storia eruttiva
    Beschreibung: JCR Journal
    Schlagwort(e): lava, volcanic source modeling, synthetic aperture radar, optical images, change detection, hierarchical-split-based approach, DInSAR coherence, Fogo volcano
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 10
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    On the use of satellite Remote Sensing for detecting surface effects due to subsurface processes (2018)
    Details
    Publikationsdatum: 2019-12-05
    Beschreibung: Nowadays, satellite Remote Sensing accounts for a wide range of instruments and sensors with an unprecedented capability to study the physical processes causing earthquakes, volcanic eruptions, slope instabilities, and the effects of human activities, like mining, aquifer exploitation, fluids extraction. Remote Sensing allows the systematic observation of the Earth surface covering large areas (up to hundreds km2), over long time period (up to annual scales). In particular, the novel generation of Synthetic Aperture Radar (SAR) and Optical missions have significantly improved the capability to detect changes in the scene and, thanks to innovative processing algorithms, to measure displacements with increased accuracies (up to mm scales). This is the case of Interferometric SAR (InSAR) and Advanced-InSAR techniques that demonstrated their effectiveness to investigate crustal faulting stemming from the detection of surface deformation patterns. Moreover, during a seismic sequence, satellite data are used to map damages in built areas and coseismic deformation due to the main earthquakes. In volcanic studies InSAR allows measuring pre-eruptive inflation, co-eruptive deflation and the post-eruptive response. The spatial-temporal evolution of volcanic processes, the “breathing” of a volcano, can be monitored with temporal series of InSAR interferograms using multitemporal InSAR techniques. The measured deformation can be used as a constraint for the formulation of the inverse problem, i.e., to retrieve information concerning the depth, size, shape of the magmatic source. Finally, natural and anthropogenic subsidence can be monitored over long temporal span in order to follow their evolution and possible impact on the environment.
    Beschreibung: Published
    Beschreibung: St. Petersburg, Russia
    Beschreibung: 6T. Variazioni delle caratteristiche crostali e precursori
    Schlagwort(e): Remote sensing ; Subsurface processes
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Conference paper
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