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Origin and evolution of late discrete eruptive activity in long dormant volcanic province: the case of the Monts Dore stratovolcano (France)

Manon Pouget1 , Guillaume Boudoire1, Nicolas Cluzel1, Clara Gorce1, Fausto Grassa2, Étienne Médard1, Federica Schiavi1, Andrea Luca Rizzo3, Pierre-Jean Gauthier1, Vittorio Zanon4, Séverine Moune1

  • Affiliations: 1Laboratoire Magmas et Volcans, Université Clermont-Auvergne, CNRS, IRD, OPGC, Clermont-Ferrand, France; 2Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo, Palermo, Italia; 3Department of Earth and Environmental Sciences, University of Milano-Bicocca, Milano, Italia; 4Complexo Científico, Universidade dos Açores, Ponta Delgada, Portugal 

  • Presentation type: Poster

  • Presentation time: Thursday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 231

  • Programme No: 1.1.17

  • Theme 1 > Session 1

Abstract

In a world where volcanic eruptions are among the most significant natural hazards to humanity, quiescent volcanic provinces play a unique role. The lack of a collective memory of past eruptions often encourages local populations to settle in these areas. However, long periods of quiescence can lead to the accumulation of energy at depth, potentially resulting in violent eruptions. To mitigate disaster risks and detect potential changes in activity, it is crucial to understand the past behavior of these currently quiescent volcanic provinces and develop effective monitoring strategies. Although the last major phase of activity in the Mont Dore volcanic province (France) occurred approximately 200,000 years ago, discrete eruptive events took place sparsely until 7,000 years ago. An unusual seismic swarm in 2021-2022 highlighted the gaps in knowledge regarding these late eruptive events, particularly in the vicinity of the seismic activity. To address this, a multidisciplinary approach combining the study of magmatic inclusions and pyroxene crystals is employed to constrain the architecture of the underlying magmatic system and to understand the evolution of magmas and fluids within it. Using this model, the chemistry of surface gaseous emissions is analysed to provide insights into the current state of the volcanic province. Seven sites were sampled, as well as two in the Chaîne des Puys (France) for comparison purposes. Whole-rock compositions range from basanite to trachy-basalt (43.0-46.8 wt.% SiO2; 4.2-6.5 wt.% Na2O+K2O). First analyses of the melt inclusions seem to show a diversity of compositions that is at least as great.