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Villeneuve, N.
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Villeneuve, N.
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- PublicationRestrictedConclusion: recommendations and findings of the RED SEED working group(The Geological Society of London, 2016)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Harris, A. J. L. ;Carn, S. ;Dehn, J. ;Del Negro, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Gudmundsson, M. T. ;Cordonnier, B. ;Barnie, T. ;Chahi, E. ;Calvari, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Catry, T. ;De Groeve, T. ;Coppola, D. ;Davies, A. ;Favalli, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Ferrucci, F. ;Fujita, E. ;Ganci, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Garel, F. ;Huet, P. ;Kauahikaua, J. ;Kelfoun, K. ;Lombardo, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Macedonio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Pacheco, J. ;Patrick, M. ;Pergola, N. ;Ramsey, M. ;Rongo, R. ;Sahy, F. ;Smith, K. ;Tarquini, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Thordarson, T. ;Villeneuve, N. ;Webley, P. ;Wright, R. ;Zaksek, K. ; ; ;; ; ; ; ;; ; ; ; ;; ; ;; ; ; ; ;; ; ; ; ; ; ; ; ;; ; ; ; ; ;; ; ; ; ;Harris, A. J. L. ;De Groeve, T. ;Garel, F.Carn, S. A.RED SEED stands for Risk Evaluation, Detection and Simulation during Effusive Eruption Disasters, and combines stakeholders from the remote sensing, modelling and response communities with experience in tracking volcanic effusive events. The group first met during a three day-long workshop held in Clermont Ferrand (France) between 28 and 30 May 2013. During each day, presentations were given reviewing the state of the art in terms of (a) volcano hot spot detection and parameterization, (b) operational satellite-based hot spot detection systems, (c) lava flow modelling and (d) response protocols during effusive crises. At the end of each pre- sentation set, the four groups retreated to discuss and report on requirements for a truly integrated and operational response that satisfactorily combines remote sensors, modellers and responders during an effusive crisis. The results of collating the final reports, and follow-up discussions that have been on-going since the workshop, are given here. We can reduce our discussions to four main findings. (1) Hot spot detection tools are operational and capable of providing effusive erup- tion onset notice within 15 min. (2) Spectral radiance metrics can also be provided with high degrees of confidence. However, if we are to achieve a truly global system, more local receiving stations need to be installed with hot spot detection and data processing modules running on-site and in real time. (3) Models are operational, but need real-time input of reliable time-averaged discharge rate data and regular updates of digital elevation models if they are to be effective; the latter can be provided by the radar/photogrammetry community. (4) Information needs to be provided in an agreed and standard format following an ensemble approach and using models that have been validated and recognized as trustworthy by the responding authorities. All of this requires a sophisticated and centralized data collection, distribution and reporting hub that is based on a philosophy of joint ownership and mutual trust. While the next chapter carries out an exercise to explore the viability of the last point, the detailed recommendations behind these findings are detailed here.308 47 - PublicationOpen AccessNew geological insights and structural control on fluid circulation in La Fossa cone (Vulcano, Aeolian Islands, Italy)(2009)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Barde-Cabusson, S.; Dipartimento di Scienze della Terra, Università Degli Studi di Firenze, Italy; LMV, Université Blaise Pascal, Clermont-Ferrand, France ;Finizola, A.; Laboratoire GéoSciences Réunion, UR, IPGP, UMR 7154, Saint-Denis, La Réunion, France; Istituto Nazionale di Geofisica e Vulcanologia, Palermo, Italy ;Revil, A.; Colorado School of Mines, Dept. of Geophysics, Golden, CO, USA; CNRS-LGIT (UMR 5559), University of Savoie, Equipe Volcan, Chambéry, France ;Ricci, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Piscitelli, S.; IMAA-CNR, Laboratory of Geophysics Tito Scalo (PZ), Italy ;Rizzo, E.; IMAA-CNR, Laboratory of Geophysics Tito Scalo (PZ), Italy ;Angeletti, B.; CNRS-CEREGE, Université Paul Cézanne, Aix en Provence, France ;Balasco, M.; IMAA-CNR, Laboratory of Geophysics Tito Scalo (PZ), Italy ;Bennati, L.; Dept. of Earth & Atmospheric Sciences, Purdue University, West Lafayette, USA ;Byrdina, S.; LMV, Université Blaise Pascal, Clermont-Ferrand, France; Equipe de Géomagnétisme, IPGP, UMR 7154, 4, Place Jussieu, 75005 Paris, France ;Carzaniga, N.; Dipartimento di Scienze della Terra, Università Degli Studi di Firenze, Italy ;Crespy, A.; CNRS-CEREGE, Université Paul Cézanne, Aix en Provence, France ;Di Gangi, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Morin, J.; Laboratoire GéoSciences Réunion, UR, IPGP, UMR 7154, Saint-Denis, La Réunion, France; Université Paris 1, Panthéon-Sorbonne, Paris, France ;Perrone, A.; IMAA-CNR, Laboratory of Geophysics Tito Scalo (PZ), Italy ;Rossi, M.; Dipartimento di Geoscienze, Università di Padova, Italy; Università Milano-Bicocca, Milan, Italy ;Roulleau, E.; GEOTOP-UQAM-McGill, Montréal, Canada ;Suski, B.; Université de Lausanne (UNIL), Institut de Géophysique, Lausanne, Switzerland; CNRS-CEREGE, Université Paul Cézanne, Aix en Provence, France ;Villeneuve, N.; Institut de Recherche pour le Développement, US 140 ESPACE, La Réunion, France; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Electric resistivity tomography (ERT), self-potential (SP), soil CO2 flux, and temperature are used to study the inner structure of La Fossa cone (Vulcano, Aeolian Islands). Nine profiles were performed across the cone with a measurement spacing of 20 m. The crater rims of La Fossa cone are underlined by sharp horizontal resistivity contrasts. SP, CO2 flux, and temperature anomalies underline these boundaries which we interpret as structural limits associated to preferential circulation of fluids. The Pietre Cotte crater and Gran Cratere crater enclose the main hydrothermal system, identified at the centre of the edifice on the base of low electrical resistivity values (b20 Ω m) and strong CO2 degassing, SP, and temperature anomalies. In the periphery, the hydrothermal activity is also visible along structural boundaries such as the Punte Nere, Forgia Vecchia, and Palizzi crater rims and at the base of the cone, on the southern side of the edifice, along a fault attributed to the NW main tectonic trend of the island. Inside the Punte Nere crater, the ERT sections show an electrical resistive body that we interpret as an intrusion or a dome. This magmatic body is reconstructed in 3D using the available ERT profiles. Its shape and position, with respect to the Pietre Cotte crater fault, allows replacing this structure in the chronology of the development of the volcano. It corresponds to a late phase of activity of the Punte Nere edifice. Considering the position of the SP, soil CO2 flux, and temperature maxima and the repartition of conductive zones related to hydrothermal circulation with respect to the main structural features, La Fossa cone could be considered as a relevant example of the strong influence of preexisting structures on hydrothermal fluid circulation at the scale of a volcanic edifice.615 1351 - PublicationUnknownShallow system rejuvenation and magma discharge trends at Piton de la Fournaise volcano (La Réunion Island)(2017)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ;Basaltic magma chambers are often characterized by emptying and refilling cycles that influence their evolution in space and time, and the associated eruptive activity. During April 2007, the largest historical eruption of Piton de la Fournaise (Île de La Réunion, France) drained the shallow plumbing system () and resulted in collapse of the 1-km-wide summit crater. Following these major events, Piton de la Fournaise entered a seven-year long period of near-continuous deflation interrupted, in June 2014, by a new phase of significant inflation. By integrating multiple datasets (lava discharge rates, deformation, seismicity, gas flux, gas composition, and lava chemistry), we here show that the progressive migration of magma from a deeper (below sea level) storage zone gradually rejuvenated and pressurized the above-sea-level portion of the magmatic system consisting of a vertically-zoned network of relatively small-volume magma pockets. Continuous inflation provoked four small () eruptions from vents located close to the summit cone and culminated, during August–October 2015, with a chemically zoned eruption that erupted of lava. This two-month-long eruption evolved through (i) an initial phase of waning discharge, associated to the withdrawal of differentiated magma from the shallow system, into (ii) a month-long phase of increasing lava and SO2 fluxes at the effusive vent, coupled with CO2 enrichment of summit fumaroles, and involving emission of less differentiated lavas, to end with, (iii) three short-lived (∼2 day-long) pulses in lava and gas flux, coupled with arrival of cumulative olivine at the surface and deflation. The activity observed at Piton de la Fournaise in 2014 and 2015 points to a new model of shallow system rejuvenation and discharge, whereby continuous magma supply causes eruptions from increasingly deeper and larger magma storage zones. Downward depressurization continues until unloading of the deepest, least differentiated magma triggers pulses in lava and gas flux, accompanied by rapid contraction of the volcano edifice, that empties the main shallow reservoir and terminates the cycle. Such an unloading process may characterize the evolution of shallow magmatic systems at other persistently active effusive centers.314 16 - PublicationRestrictedInvestigating the deepest part of a volcano plumbing system: Evidence for an active magma path below the western flank of Piton de la Fournaise (La Réunion Island)(2017)
; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ;; ; ; ; ;; Peripheral diffuse degassing of CO2 from the soil occurs across the western flank of Piton de la Fournaise volcano (La Réunion Island, Indian Ocean) along a narrow zone. In this area, carbon isotopic analysis on soil gas samples highlights significant mixing between magmatic and organic end-members. The zones with the strongest magmatic signature (highest δ13C) overlap spatial distribution of hypocenters recorded shortly before and during volcano reactivation and allow discriminating a N135° degassing lineament, with a minimum length of 11 km and 140 ± 20 m-width. Such orientation is in accordance with that of an old dyke network along the rift zone and with N120–130° and N140–155° lineaments related to the inheritance of oceanic lithosphere structures. Our findings show that this N135° lineament represents a preferential magmatic pathway for deep magma transfer below the volcano flank. Moreover, spatial distributions of recent eccentric cones indicate a well-founded possibility that future eruptions may by-pass the shallow plumbing system of the central area of the volcano, taking a lateral pathway along this structure. Our results also confirm that Piton de la Fournaise activity is linked to a laterally shifted plumbing system and represent a major improvement in identifying the main high-risk area on the densely populated western flank of the volcano309 7