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University of Bristol, Bristol, UK
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- PublicationRestrictedDeveloping an Event Tree for probabilistic hazard and risk assessment at Vesuvius(2008)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Neri, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Aspinall, W. P.; University of Bristol, Bristol, UK ;Cioni, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Bertagnini, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Baxter, P. J.; Institute of Public Health, University of Cambridge, Cambridge, UK ;Zuccaro, G.; Centro PLINIUS-LUPT, Università degli Studi di Napoli “Federico II”, Italy ;Andronico, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Barsotti, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Cole, P. D.; Department of Geography, Environment and Disaster Management, University of Coventry, Coventry, UK ;Esposti Ongaro, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Hincks, T. K.; University of Bristol, Bristol, UK ;Macedonio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Papale, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Rosi, M.; Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy ;Santacroce, R.; Università di Pisa, Pisa, Italy ;Woo, G.; Aspinall and Associates, UK; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Probabilistic characterizations of possible future eruptive scenarios at Vesuvius volcano are elaborated and organized within a risk-based framework. In the EXPLORIS project, a wide variety of topics relating to this basic problem have been pursued: updates of historical data, reinterpretation of previous geological field data and the collection of new fieldwork results, the development of novel numerical modelling codes and of risk assessment techniques have all been completed. To achieve coherence, many diverse strands of evidence had to be unified within a formalised structure, and linked together by expert knowledge. For this purpose, a Vesuvius ‘Event Tree’ (ET) was created to summarise in a numerical-graphical form, at different levels of detail, all the relative likelihoods relating to the genesis and style of eruption, development and nature of volcanic hazards, and the probabilities of occurrence of different volcanic risks in the next eruption crisis. The Event Tree formulation provides a logical pathway connecting generic probabilistic hazard assessment to quantitative risk evaluation. In order to achieve a complete parameterization for this all-inclusive approach, exhaustive hazard and risk models were needed, quantified with comprehensive uncertainty distributions for all factors involved, rather than simple ‘best-estimate’ or nominal values. Thus, a structured expert elicitation procedure was implemented to complement more traditional data analysis and interpretative approaches. The structure of the Vesuvius Event Tree is presented, and some of the data analysis findings and elicitation outcomes that have provided initial indicative probability distributions to be associated with each of its branches are summarized. The Event Tree extends from initiating volcanic eruption events and hazards right through to human impact and infrastructure consequences, with the complete tree and its parameterisation forming a quantitative synoptic framework for comprehensive hazard evaluation and mapping of risk impacts. The organization of the Event Tree allows easy updating, as and when new information becomes available335 50 - PublicationRestrictedQuantitative assessment of volcanic ash hazards for health and infrastructure at Mt. Etna (Italy) by numerical simulation(2010-04-20)
; ; ; ; ; ; ; ;Barsotti, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Andronico, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Neri, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Del Carlo, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Baxter, P. J.; Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK ;Aspinall, W. P.; Department of Earth Sciences, University of Bristol, Bristol, UK; Aspinall & Assocs., Cleveland House, Tisbury, UK ;Hincks, T.; Department of Earth Sciences, University of Bristol, Bristol, UK; ; ; ; ; ; We performed a quantitative hazard assessment to determine the potential impacts of volcanic tephra fall on human health and infrastructure in the vicinity of Mt. Etna (Italy). Using the numerical model VOL-CALPUFF, we explored the dynamics of long-lasting weak plume eruptions and their effects on the surrounding region. Input data are based on credible estimates of the main parameters characterising the expected events as derived from the historically observed and reconstructed explosive record of Mt. Etna. Monte Carlo techniques are used to capture the effects on estimates of finer ash concentration and total ground deposition due to volcanological uncertainties and meteorological variability. Numerical simulations compute the likelihoods of experiencing critical 10-μm volcanic particle (VP10) concentrations in ambient air and tephra ground deposition at various populated locations around the volcano, including the city of Catania, and at key infrastructure, such as airports and main roads. Results show how the towns and infrastructure on the east side of the volcano are significantly more exposed to ash-related hazards than those on the west side, in accordance with wind statistics. Simulation outcomes also illustrate how, at the sites analysed, the amount of deposited particulate matter is proportional to the intensity (i.e. mass flow rate) of the event whereas predicted values of VP10 concentrations are significantly larger for smaller events due to the reduced dispersal of low altitude plumes. The use of a simple re-mobilization model highlights the fact that particle re-suspension needs to be considered in the estimation of VP10 values. Our findings can be used to inform civil protection agencies responsible for mitigating tephra fall impacts to human health, road transport and aviation safety.226 28 - PublicationOpen AccessMagmatism on rift flanks: Insights from ambient noise phase velocity in Afar region(2015-03)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; During the breakup of continents in magmatic settings, the extension of the rift valley is commonly assumed to initially occur by border faulting and progressively migrate in space and time toward the spreading axis. Magmatic processes near the rift flanks are commonly ignored. We present phase velocity maps of the crust and uppermost mantle of the conjugate margins of the southern Red Sea (Afar and Yemen) using ambient noise tomography to constrain crustal modification during breakup. Our images show that the low seismic velocities characterize not only the upper crust beneath the axial volcanic systems but also both upper and lower crust beneath the rift flanks where ongoing volcanism and hydrothermal activity occur at the surface. Magmatic modification of the crust beneath rift flanks likely occurs for a protracted period of time during the breakup process and may persist through to early seafloor spreading.249 14