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Shreve T., Grandin R., Boichu M., Garaebiti E., Moussallam Yves, Ballu V., Delgado F., Leclerc F., Vallée Martin, Henriot N., Cevuard S., Tari D., Lebellegard Pierre, Pelletier Bernard. (2019). From prodigious volcanic degassing to caldera subsidence and quiescence at Ambrym (Vanuatu) : the influence of regional tectonics. Scientific Reports - Nature, 9, p. art. 18868 [13 p.]. ISSN 2045-2322.

Titre du document
From prodigious volcanic degassing to caldera subsidence and quiescence at Ambrym (Vanuatu) : the influence of regional tectonics
Année de publication
2019
Type de document
Article référencé dans le Web of Science WOS:000502616600001
Auteurs
Shreve T., Grandin R., Boichu M., Garaebiti E., Moussallam Yves, Ballu V., Delgado F., Leclerc F., Vallée Martin, Henriot N., Cevuard S., Tari D., Lebellegard Pierre, Pelletier Bernard
Source
Scientific Reports - Nature, 2019, 9, p. art. 18868 [13 p.] ISSN 2045-2322
Eruptive activity shapes volcanic edifices. The formation of broad caldera depressions is often associated with major collapse events, emplacing conspicuous pyroclastic deposits. However, caldera subsidence may also proceed silently by magma withdrawal at depth, more difficult to detect. Ambrym, a basaltic volcanic island, hosts a 12-km wide caldera and several intensely-degassing lava lakes confined to intra-caldera cones. Using satellite remote sensing of deformation, gas emissions and thermal anomalies, combined with seismicity and ground observations, we show that in December 2018 an intra-caldera eruption at Ambrym preceded normal faulting with >2 m of associated uplift along the eastern rift zone and 2.5 m of caldera-wide subsidence. Deformation was caused by lateral migration of >0.4 cubic kilometers of magma into the rift zone, extinguishing the lava lakes, and feeding a submarine eruption in the rift edge. Recurring rifting episodes, favored by stress induced by the D'Entrecasteaux Ridge collision against the New Hebrides arc, lead to progressive subsidence of Ambrym's caldera and concurrent draining of the lava lakes. Although counterintuitive, convergent margin systems can induce rift zone volcanism and subsequent caldera subsidence.
Plan de classement
Géologie et formations superficielles [064] ; Géophysique interne [066]
Description Géographique
VANUATU ; AMBRYM ILE
Localisation
Fonds IRD [F B010077480]
Identifiant IRD
fdi:010077480
Contact