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  • 1
    Publication Date: 2020-03-09
    Description: Magmas discharged during individual volcanic eruptions commonly display compositional variations interpreted as new arrivals at shallow depth of more primitive, hotter, volatile-rich magma batches mixing with resident, colder, partially degassed magma. Heterogeneities in eruption products are often interpreted as evidence of short times of order tens of hours from new magma arrival to eruption, raising concerns for emergency planning. We show here, through numerical simulations, that magma convection and mixing in a shallow magma chamber can result in long-lived, dynamically stable configurations with coexistence of magmas from nearly pure to variably mixed end-member compositions. Short mixing time scales may therefore relate to sin-eruptive processes, as heterogeneities found in the eruptive products are not necessarily the fingerprint of new magma arrival shortly preceding or triggering the eruption.
    Description: Published
    Description: id 3321
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2019-03-28
    Description: This work aims to develop a numerical wave tank for viscous and inviscid flows. The Navier-Stokes equations are solved by timediscontinuous stabilized space-time finite element method. The numerical scheme tracks the free surface location using fluid velocity. A segregated algorithm is proposed to iteratively couple the fluid flow and mesh deformation problems. The numerical scheme and the developed computer code are validated over three free surface problems: solitary wave propagation, the collision between two counter moving waves, and wave damping in a viscous fluid. The benchmark tests demonstrate that the numerical approach is effective and an attractive tool for simulating viscous and inviscid free surface flows.
    Description: Published
    Description: ID 6154251
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    Publication Date: 2019-03-28
    Description: This paper presents the numerical results of compressible and incompressible flow problems through a unified approach based on a stabilized space–time finite element method. The numerical approach is continuous in space and discontinuous in time. The proposed method starts by the use of a stabilized space–time variational formulation, which allows the use of the same order interpolation functions for all solution variables. The numerical technique is tested through comparison with standard compressible and incompressible flow benchmarks. Compressible flow cases include 1D and 2D shock problems. Incompressible flow cases include lid-driven cavity flow and flow over a backward-facing step computed over a range of Re numbers. The results demonstrate high stability and accuracy of the numerical technique over a wide range of flow regimes, suggesting straightforward extension to many flow cases not yet investigated.
    Description: Published
    Description: 4272–4285
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
    Publication Date: 2022-04-21
    Description: The dynamics of magma is often studied through 2D numerical simulations because 3D simulations are usually complex and computationally expensive. However, magmatic systems and physical processes are 3D and approximating them in 2D requires an evaluation of the information which is lost under different conditions. This work presents a physical and numerical model for 3D magma convection dynamics. The model is applied to study the dynamics of magma convection and mixing between andesitic and dacitic magmas. The 3D simulation results are compared with corresponding 2D simulations. We also provide details on the numerical scheme and its parallel implementation in C++ for high-performance computing. The performance of the numerical code is evaluated through strong scaling exercises involving up to 〉 12,000 cores.
    Description: Published
    Description: 760773
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
    Publication Date: 2022-02-11
    Description: In this work, a partitioned fluid-structure interaction solver is presented. Fluid flow problem is solved with time-discontinuous deforming domain stabilized space-time finite element method. Flow is computed with pressure primitive variables which permit to use the same numerical technique for both compressible and incompressible regimes. Elastic deformation of the structure is modelled in the Lagrangian frame of reference with Saint-Venant Kirchhoff and Neo-Hookean material models - both are non-linear and valid for large deformations. Structure equations are discretized with Galerkin finite element method for space and with generalized-alpha method for the time. Mesh motion is modelled with the elastic deformation method. An implicit algorithm is presented to couple the different solvers. The details are provided on the implementation of the solvers in parallel software. The numerical code is verified and validated on several compressible and incompressible flow benchmarks widely used in the literature. The results demonstrate that the developed solver successfully detects the accurate interaction between fluid and structure.
    Description: Published
    Description: 182-195
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 6
    Publication Date: 2022-02-11
    Description: Knowledge of the global distribution of Earth volcanism is critical in many fields of the Geosciences involving large-scale assessments, such as plate tectonics, global volcanic hazards, and climate change. Recent analysis has revealed that global eruption inter-event times are exponentially distributed, implying that on the global scale volcanic eruptions are Poisson distributed. Here, we employ those findings to calibrate a continuous frequency-volume distribution for subaerial eruptions of any size on Earth from small lava flows to super-eruptions. Obtaining such a continuous global distribution implies considering the existing data and the way they are collected and categorized into databases, as well as extending the available eruption volume data to eruption VEI classes less than 4. The continuous global distribution shows an initial log-normal section up to volumes of about 170 Mm3, followed by a power-law section, tapered on its extreme right-end side, encompassing about five orders of magnitude of eruption volumes. The potential implications are discussed in terms of short-term eruption forecasts of the size of an impending eruption, critical for volcanic emergency management.
    Description: Published
    Description: e2021JB021763
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 7
    Publication Date: 2023-02-27
    Description: Knowledge of the global rates of volcanism is fundamental for modeling the Earth, as those rates closely relate to plate tectonics, crustal growth, mantle dynamics, atmospheric evolution, climate change, and virtually any aspect of the global Earth dynamics. In spite of their huge relevance, the global rates of volcanism have remained unknown, hidden within data that appeared disordered, largely fragmented and incomplete, reflecting poor preservation of small eruptions in the geological record, rareness of large eruptions, and distributions far from normal. Here we describe and validate a model that reproduces global volcanism to high statistical significance, and that is so simple to comfortably fit on a t-shirt. We use the model to compute the expected rates of global terrestrial volcanism over time windows from 1 to 100,000 years, and validate it by comparing with observations back to a few million years. Notably, the model can be tested against independent observations collected in the near future, a feature which is relatively uncommon among global models of Solid Earth dynamics.
    Description: Published
    Description: 922160
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 8
    Publication Date: 2023-02-27
    Description: Volcano science has been deeply developing during last decades, from a branch of descriptive natural sciences to a highly multi-disciplinary, technologically advanced, quantitative sector of the geosciences. While the progress has been continuous and substantial, the volcanological community still lacks big scientific endeavors comparable in size and objectives to many that characterize other scientific fields. Examples include large infrastructures such as the LHC in Geneva for sub-atomic particle physics or the Hubble telescope for astrophysics, as well as deeply coordinated, highly funded, decadal projects such as the Human Genome Project for life sciences. Here we argue that a similar big science approach will increasingly concern volcano science, and briefly describe three examples of developments in volcanology requiring such an approach, and that we believe will characterize the current decade (2020–2030): the Krafla Magma Testbed initiative; the development of a Global Volcano Simulator; and the emerging relevance of big data in volcano science.
    Description: Published
    Description: 20
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 9
    Publication Date: 2023-01-16
    Description: Active magma chambers are periodically replenished upon a combination of buoyancy and pressure forces driving upward motion of initially deep magma. Such periodic replenishments concur to determine the chemical evolution of shallow magmas, they are often associated to volcanic unrests, and they are nearly ubiquitously found to shortly precede a volcanic eruption. Here we numerically simulate the dynamics of shallow magma chamber replenishment by systematically investigating the roles of buoyancy and pressure forces, from pure buoyancy to pure pressure conditions and across combinations of them. Our numerical results refer to volcanic systems that are not frequently erupting, for which magma at shallow level is isolated from the surface (â\euroœclosed conduitâ\euro? volcanoes). The results depict a variety of dynamic evolutions, with the pure buoyant end-member associated with effective convection and mixing and generation of no or negative overpressure in the shallow chamber, and the pure pressure end-member translating into effective shallow pressure increase without any dynamics of magma convection associated. Mixed conditions with variable extents of buoyancy and pressure forces illustrate dynamics initially dominated by overpressure, then, over the longer term, by buoyancy forces. Results globally suggest that many shallow magmatic systems may evolve during their lifetime under the control of buoyancy forces, likely triggered by shallow magma degassing. That naturally leads to long-term stable dynamic conditions characterized by periodic replenishments of partially degassed, heavier magma by volatile-rich fresh deep magma, similar to those reconstructed from petrology of many shallow-emplaced magmatic bodies.
    Description: Published
    Description: e2022JB025316
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 10
    Publication Date: 2024-01-29
    Description: Volcano geodesy often involves the use of models to explain observed surface deformation. A variety of forward models are used, from analytical point sources to numerical simulations that consider complex magma system geometries, topography, and material properties. Various inversion methods can then be used to relate observed volcano data to models. Ideally, forward models should be verified through intercomparison, to check for implementation errors and quantify the error induced by any approximations used. Additionally, forward models and inversion methods should be validated through tests with synthetic and/or real data, to determine their ability to match data and estimate parameter values within uncertainty. However, to date, there have not been comprehensive verification and validation efforts in volcano geodesy. Here, we report on the first phase of the Drivers of Volcano Deformation (DVD) exercises, which were designed to build community involvement through web-based exercises involving calculations of static elastic displacement around pressurized magma reservoirs. The forward model exercises begin with a spherical reservoir in a homogeneous half space, then introduce topography, heterogeneous elastic properties, and spheroidal geometries. The inversion exercises provide synthetic noisy surface displacement data for a spherical reservoir in a homogeneous half space and assess consistency in estimates of reservoir location and volume/pressure change. There is variability in the results from both forward modeling and inversions, which highlights the strengths and limitations of different forward models, as well as the importance of inversion method choice and uncertainty quantification. This first phase of the DVD exercises serves as a community resource and will facilitate further efforts to develop standards of reproducibility.
    Description: Published
    Description: 74
    Description: OSV3: Sviluppo di nuovi sistemi osservazionali e di analisi ad alta sensibilità
    Description: JCR Journal
    Keywords: 04.08. Volcanology ; 04.03. Geodesy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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