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Decadal to monthly timescales of magma transfer and reservoir growth at a caldera volcano
Druitt T., Costa Rodriguez F., Dungan M., Scaillet B.
Nature 482 (2012) 77-82 - http://hal-insu.archives-ouvertes.fr/insu-00666208
Articles dans des revues avec comité de lecture
Planète et Univers/Sciences de la Terre/Volcanologie
Sciences de l'environnement/Milieux et Changements globaux
Decadal to monthly timescales of magma transfer and reservoir growth at a caldera volcano
T. Druitt () 1, 2, Fidel Costa Rodriguez 3, M. Dungan 4, Bruno Scaillet () 5
1 :  Laboratoire Magmas et Volcans (LMV)
http://wwwobs.univ-bpclermont.fr/lmv/
CNRS : UMR6524 – Institut de recherche pour le développement [IRD] – INSU – Université Blaise Pascal - Clermont-Ferrand II – Université Jean Monnet - Saint-Etienne
5 Rue Kessler 63038 CLERMONT FERRAND CEDEX 1
France
2 :  IRD R 163
Institut de recherche pour le développement [IRD]
France
3 :  Earth Observatory of Singapore
Nanyang Technological University
Singapour
4 :  Deépartement de Minéralogie
Université de Genève
Rue des Maraıˆchers, 13 CH-1205 Gene' ve,
Suisse
5 :  GéoHydrosystèmes COntinentaux (GéhCO EA6293)
Université François Rabelais - Tours
France
Caldera-forming volcanic eruptions are low-frequency, highimpact events capable of discharging tens to thousands of cubic kilometres of magma explosively on timescales of hours to days, with devastating effects on local and global scales1. Because no such eruption has been monitored during its long build-up phase, the precursor phenomena are not well understood. Geophysical signals obtained during recent episodes of unrest at calderas such as Yellowstone, USA, and Campi Flegrei, Italy, are difficult to interpret, and the conditions necessary for large eruptions are poorly constrained2,3. Here we present a study of pre-eruptive magmatic processes and their timescales using chemically zoned crystals from the 'Minoan' caldera-formingeruption of Santorini volcano,Greece4, which occurred in the late 1600s BC. The results provide insights into how rapidly large silicic systems may pass from a quiescent state to one on the edge of eruption5,6. Despite the large volume of erupted magma4 (40-60 cubic kilometres), and the 18,000-year gestation period between the Minoan eruption and the previous major eruption, most crystals in the Minoan magma record processes that occurred less than about 100 years before the eruption. Recharge of the magma reservoir by large volumes of silicic magma (and some mafic magma) occurred during the century before eruption, and mixing between different silicicmagmabatches was still taking place during the final months. Final assembly of large silicic magma reservoirs may occur on timescales that are geologically very short by comparison with the preceding repose period, with major growth phases immediately before eruption. These observations have implications for the monitoring of long-dormant, but potentially active, caldera systems.
Anglais

Nature (Nature)
Publisher Nature Publishing Group
ISSN 0028-0836 (eISSN : 1476-4679)
internationale
2012
482
77-82

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