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Cavazzoni, C.
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Cavazzoni, C.
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- PublicationRestricted4D simulation of explosive eruption dynamics at Vesuvius(2007-02-24)
; ; ; ; ; ; ; ;Neri, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Esposti Ongaro, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Menconi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;De' Michieli Vitturi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Cavazzoni, C.; High Performance Computing Group, Consorzio Interuniversitario per il Calcolo Automatico dell'Italia Nord Orientale, Bologna, Italy ;Erbacci, G.; High Performance Computing Group, Consorzio Interuniversitario per il Calcolo Automatico dell'Italia Nord Orientale, Bologna, Italy ;Baxter, P. J.; Institute of Public Health, University of Cambridge, Cambridge, UK; ; ; ; ; ; We applied a new simulation model, based on multiphase transport laws, to describe the 4D (3D spatial coordinates plus time) dynamics of explosive eruptions. Numerical experiments, carried out on a parallel supercomputer, describe the collapse of the volcanic eruption column and the propagation of pyroclastic density currents (PDCs), for selected medium scale (sub-Plinian) eruptive scenarios at Vesuvius, Italy. Simulations provide crucial insights into the effects of the generation mechanism of the flows - partial collapse vs boiling-over - on their evolution and hazard potential, the unstable dynamics of the fountain, and the influence of Mount Somma on the propagation of PDCs into the circum-Vesuvian area, one of the world's most hazardous volcanic settings. Results also show that it is possible to characterize the volcanic column behavior in terms of percentage of the mass of pyroclasts collapsed to the ground and how this parameter strongly influences the dynamics and hazard of the associated PDCs.222 28 - PublicationOpen AccessAn interactive virtual Environment to comunicate Vesuvius eruptions numerical simulations and Pompeii history(2006)
; ; ; ; ; ; ; ; ; ; ; ; ; ;Guidazzoli, A.; CINECA ;Diamanti, T.; CINECA ;Delli Ponti, F.; CINECA ;Neri, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Bisson, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Esposti Ongaro, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Gori, R.; CINECA ;Pareschi, M. T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Calori, L.; CINECA ;Imboden, S.; CINECA ;Cavazzoni, C.; CINECA ;Erbacci, G.; CINECA ;Menconi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; ; ; ; ; ; ; ; ; ; ; ; in the file343 724 - PublicationRestrictedTransient 3D numerical simulations of column collapse and pyroclastic density current scenarios at Vesuvius(2008)
; ; ; ; ; ; ; ; ;Esposti Ongaro, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Neri, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Menconi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;De' Michieli Vitturi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Marianelli, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Cavazzoni, C.; Cineca, High Performance Computing Group, Casalecchio di Reno, Italia ;Erbacci, G.; Cineca, High Performance Computing Group, Casalecchio di Reno, Italia ;Baxter, P. J.; Institute of Public Health, University of Cambridge, Cambridge, UK; ; ; ; ; ; ; Numerical simulations of column collapse and pyroclastic density current (PDC) scenarios at Vesuvius were carried out using a transient 3D flow model based on multiphase transport laws. The model describes the complex dynamics of the collapse as well as the effects of the 3D topography of the volcano on PDC propagation. Source conditions refer to a medium-scale sub-Plinian event and consider a pressure-balanced jet. Simulation results provide new insights into the complex dynamics of these phenomena. In particular: 1) column collapse can be characterized by different regimes, from incipient collapse to partial or nearly total collapse, thus confirming the possibility of a transitional field of behaviour of the column characterized by the contemporaneous and/or intermittent occurrence of ash fallout and PDCs; 2) the collapse regime can be characterized by its fraction of eruptive mass reaching the ground and generating PDCs; 3) within the range of the investigated source conditions, the propagation and hazard potential of PDCs appear to be directly correlated with the flow-rate of the mass collapsing to the ground, rather than to the collapse height of the column (this finding is in contrast with predictions based on the energy-line concept, which simply correlates the PDC runout and kinetic energy with the collapse height of the column); 4) first-order values of hazard variables associated with PDCs (i.e., dynamic pressure, temperature, airborne ash concentration) can be derived from simulation results, thereby providing initial estimates for the quantification of damage scenarios; 5) for scenarios assuming a location of the central vent coinciding with that of the present Gran Cono, Mount Somma significantly influences the propagation of PDCs, largely reducing their propagation in the northern sector, and diverting mass toward the west and southeast, accentuating runouts and hazard variables for these sectors; 6) the 2D modelling approximation can force an artificial radial propagation of the PDCs since it ignores azimuthal flows produced by real topographies that therefore need to be simulated in fully 3D conditions.156 19 - PublicationOpen AccessIl progetto EPLORIS: La ricostruzione virtuale dell'eruzione del Vesuvio(2006)
; ; ; ; ;Cavazzoni, C.; Consorzio Interuniversitario del Nord Est Italiano per il Calcolo Automatico, Italia ;Erbacci, G.; Consorzio Interuniversitario del Nord Est Italiano per il Calcolo Automatico, Italia ;Esposti Ongaro, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Neri, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; ; ; The main objective of the Exploris project consists in the quantitative analysis of explosive eruption risk in densely populated EU volcanic regions and the evaluation of the likely effectiveness of possible mitigation measures through the development of volcanic risk facilities (such as supercomputer models, vulnerability databases, and probabilistic risk assessment protocols) and their application to high-risk European volcanoes. Exploris’ main ambition is to make a significant step forward in the assessment of explosive eruption risk in highly populated EU cities and islands. For this project, a new simulation model, based on fundamental transport laws to describe the 4D (3D spatial co-ordinates plus time) multiphase flow dynamics of explosive eruptions has been developed and parallelized in INGV and CINECA. Moreover, CINECA developed specific tools to efficiently visualise the results of simulations. This article presents the results of the large numerical simulations, carred out with CINECA’s Supercomputers, to describe the collapse of the volcanic eruption column and the propagation of pyroclastic density currents, for selected medium scale (sub-Plinian) eruptive scenarios at Vesuvius.190 153 - PublicationRestrictedAn automatic procedure to forecast tephra fallout(2008)
; ; ; ; ;Folch, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Cavazzoni, C.; Consorzio Interuniversitario CINECA, Bologna, Italy ;Costa, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Macedonio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ; Tephra fallout constitutes a serious threat to communities around active volcanoes. Reliable short-term 13 forecasts represent a valuable aid for scientists and civil authorities to mitigate the effects of fallout on the 14 surrounding areas during an episode of crisis. We present a platform-independent automatic procedure with Q1 15 the aim to daily forecast transport and deposition of volcanic particles. The procedure builds on a series of 16 programs and interfaces that automate the data flow and the execution and subsequent postprocess of fallout 17 models. Firstly, the procedure downloads regional meteorological forecasts for the area and time interval of 18 interest, filters and converts data from its native format, and runs the CALMET diagnostic model to obtain the 19 wind field and other micro-meteorological variables on a finer local-scale 3-D grid defined by the user. 20 Secondly, it assesses the distribution of mass along the eruptive column, commonly by means of the radial 21 averaged buoyant plume equations depending on the prognostic wind field and on the conditions at the vent 22 (granulometry, mass flow rate, etc). All these data serve as input for the fallout models. The initial version of 23 the procedure includes only two Eulerian models, HAZMAP and FALL3D, the latter available as serial and 24 parallel implementations. However, the procedure is designed to incorporate easily other models in a near 25 future with minor modifications on the model source code. The last step is to postprocess the outcomes of 26 models to obtain maps written in standard file formats. These maps contain plots of relevant quantities such 27 as predicted ground load, expected deposit thickness and, for the case of or 3-D models, concentration on air 28 or flight safety concentration thresholds243 33 - PublicationRestrictedParallel ‘large’ dense matrix problems: application to 3D joint inversion of seismological and gravity data(2012-11)
; ; ; ; ;Tondi, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Cavazzoni, C.; CINECA, Interuniversity Computing Centre, Via Magnanelli 6/3, 40033 Casalecchio di Reno (BO), Italy ;Danecek, P.; Univ Granada, Inst Andaluz Geofis, E-18071 Granada, Spain ;Morelli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; ; ; To obtain accurate and reliable estimations of the major lithological properties of the rock within a studied volume, geophysics uses the joint information provided by different geophysical datasets (e.g. gravimetric, magnetic, seismic). Representation of the different types of information entering the problem using probability density functions can provide the mathematical framework to formulate their combination. The maximum likelihood estimator of the resulting joint posterior probability density functions leads to the solution of the problem. However, one key problem appears to limit the use of this solver to an extensive range of real applications: information coming from potential fields that implies the presence of dense matrices in the resolving estimator. It is well known that dense matrix systems rapidly challenge both the algorithms and the computing platforms, and are not suited to high-resolution 3D geophysical analysis. In this study, we propose a procedure that allows us to obtain fast and reliable solutions of the joint posterior probability density functions in the presence of large gravity datasets and using sophisticated model parametrization. As it is particularly CPUconsuming, this 3D problem makes use of parallel computing to improve the performance and the accuracy of the simulations. Analysis of the correctness of the results, and the performance on different parallel environments, shows the portability and the efficiency of the code. This code is applied to a real experiment, where we succeed in recovering a 3D shear-wave velocity and density distribution within the upper mantle of the European continent, satisfying both the seismological and gravity data. On a multiprocessor machine, we have been able to handle forward and inverse calculations with a dense matrix of 215.66 Gb in 18 min, 20 s and 20 min, 54 s, respectively.777 104 - PublicationRestrictedA parallel multiphase flow code for the 3D simulation of explosive volcanic eruptions(2007-08)
; ; ; ; ; ;Esposti Ongaro, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Cavazzoni, C.; CINECA, Interuniversity Computing Centre, Casalecchio di Reno (BO), Italy ;Erbacci, G.; CINECA, Interuniversity Computing Centre, Casalecchio di Reno (BO), Italy ;Neri, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Salvetti, M. V.; Dip.to di Ingegneria Aerospaziale, Università degli Studi di Pisa, Pisa, Italy - Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Pisa, Pisa, Italy; ; ; ; A new parallel code for the simulation of the transient, 3D dispersal of volcanic particles in the atmosphere is presented. The model equations, describing the multiphase flow dynamics of gas and solid pyroclasts ejected from the volcanic vent during explosive eruptions, are solved by a finite-volume discretization scheme and a pressure-based iterative non-linear solver suited to compressible multiphase flows. The solution of the multiphase equation set is computationally so demanding that the simulation of the transient 3D dynamics of eruptive columns would not be cost-effective on a single workstation. The new code has been parallelized by adopting an ad hoc domain partitioning scheme that enforces the load balancing in the presence of a large number of topographic blocking-cells. An optimized communication layer has been built over the Message-Passing Interface. It is shown that the present code has a remarkable efficiency on several high-performance platforms and makes it possible, for the first time, to simulate fully 3D eruptive scenarios on realistic volcano topography.175 30 - PublicationRestrictedAn application of parallel computing to the simulation of volcanic eruptions(2009-03)
; ; ; ; ; ;Neri, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Esposti Ongaro, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Nannipieri, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Cavazzoni, C.; CINECA, Interuniversity Computing Center - Casalecchio di Reno, Bologna, Italy ;Erbacci, G; CINECA, Interuniversity Computing Center - Casalecchio di Reno, Bologna, Italy; ; ; ; A parallel code for the simulation of the transient 3D dispersal of volcanic particles produced by explosive eruptions is presented. The model transport equations, based on the multiphase flow theory, describe the atmospheric dynamics of the gas-particle mixture ejected through the volcanic crater. The numerics is based on a finite-volume discretization scheme and a pressure-based iterative non-linear solver suited to compressible multiphase flows. The code has been parallelized by adopting an ad hoc domain partitioning scheme that enforces the load balancing. An optimized communication layer has been built over the Message-Passing Interface. The code proved to be remarkably efficient on several high-performance platforms and makes it possible to simulate fully 3D eruptive scenarios on realistic volcano topography.1274 29