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Spanu, Antonio
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- PublicationOpen AccessPropagation of Source Grain-size Distribution Uncertainty by Using a Lagrangian Volcanic Particle Dispersal Model(2014)
; ; ; ; ; ; ; ; ; ; ;Lagrangian particle dispersal models are commonly used for tracking ash particles emitted from volcanic plumes and transported under the action of atmospheric wind fields. In this work, we adopted a Lagrangian particle model to carry out an uncertainty quantification analysis of volcanic ash dispersal in the atmosphere focused on the uncertainties affecting particle source conditions. To this aim the Eulerian fully compressible mesoscale non-hydrostatic model WRF was used to generate the driving wind field. The Lagrangian particle model LPAC (de’Michieli Vitturi et al., JGR 2010) was then used to simulate the transport of mass particles under the action of atmospheric conditions. The particle motion equations were derived by expressing the Lagrangian particle acceleration as the sum of the forces acting along its trajectory, with drag forces calculated as a function of particle diameter, density, shape and Reynolds number. The simulations were representative of weak plume events of Mt. Etna and aimed to quantify the effect on the dispersal process of the uncertainty in the mean and variance of a Gaussian density function describing the grain-size distribution of the mixture and in the particle sphericity. In order to analyze the sensitivity of particle dispersal to these uncertain parameters with a reasonable number of simulations, and therefore with affordable computational costs, response surfaces in the parameter space were built by using the generalized polynomial chaos technique. The uncertainty analysis allowed to quantify the most probable values, as well as their pdf, of the number of particles as well as of the mean and variance of the grain size distribution at various distances from the source, both in air and on the ground. In particular, results highlighted the strong reduction of the uncertainty ranges of the mean and variance of the grain-size distribution with increasing distance from source and the significant control of particle sphericity on the dispersal process.42 12 - PublicationOpen AccessSAFER Response to Eyjafjallajökull and Merapi Volcanic Eruptions. In: ‘Let's embrace space’ Space Research achievements under the 7th Framework Programme, Edit by European Commission, DG Enterprise and Industry(2011)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Barsotti, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Bignami, C.; Università di Modena e Reggio Emilia, Italy ;Buongiorno, M. F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Corradini, S.; Università di Modena e Reggio Emilia, Italy ;Doumaz, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Guerrieri, L.; Università di Modena e Reggio Emilia, Italy ;Merucci, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Musacchio, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Nannipieri, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Neri, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Piscini, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Silvestri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Spanu, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Spinetti, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Stramondo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Wegmuller, U.; Gamma Remote Sensing; ; ; ; ; ; ; ; ; ; ; ; ; ; ; After PREVIEW FP6 Project’s conclusion, the WP30210 within FP7 GMES SAFER (Services and Applications For Emergency Response) Project has the main objective to refine and consolidate the Earthquake & Volcanoes (E&V) services that were just tested in previous activities and to provide operative services to Users, the Civil Protection Authorities. Here we mainly report objectives and results for the specific tasks related to Eruptive volcanic parameters (WP30211). Four specific products related to the volcanic events which will contribute to the monitoring of the phenomena and mitigation of the eruption effects are expected within the end of the Project. They mainly concern: SAR displacement, high temperature events (HTE), Ash detection, SO2 concentration and flux, and Ash dispersion models. In particular, here we mostly focus on the activity performed in the occasion of FP7 GMES SAFER activation during two major volcanic eruptions occurred in 2010. The first activation was for the Eyjafjallajökull eruption occurred in Iceland between April and May 2010, and the second one was solicited in the occasion of the eruption of Mount Merapi (Indonesia) in October-November 2010. Here we present the results of both remote sensing and modeling activities performed during these two events.413 180 - PublicationOpen AccessThe lifecycle of volcanic ash: advances and ongoing challenges(2022)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ;Explosive volcanic eruptions can produce vast amounts of volcanic ash made up mainly of fragments of magmatic glass, country rock and minerals < 2 mm in size. Ash particles forming from magma fragmentation are generated by several processes when brittle response accommodates (local) deformation stress that exceeds the capability of the bulk material to respond by viscous flow. These processes span a wide range of temperatures, can occur inside or outside the volcanic edifice and can involve all melt compositions. Ash is then dispersed by volcanic and atmospheric processes over large distances and can have global distributions. Explosive eruptions have repeatedly drawn focus to studying volcanic ash. The continued occurrence of such eruptions worldwide and their widespread impacts motivates the study of the chemical and physical processes involved in the lifecycle of volcanic ash (e.g. magma fragmentation, particle aggregation), as well as the immediate to long-term effects (e.g. water and air pollution, soil fertilization) and consequences (e.g. environmental, economic, social) associated with ashfall. In this perspectives article, we reflect on the progress made over the last two decades in understanding (1) volcanic ash generation; (2) dispersion, sedimentation and erosion; and (3) impacts on the atmosphere, hydrosphere, biosphere and modern infrastructure. Finally, we discuss open questions and future challenges.57 72