Degassing at La Soufrière de Guadeloupe volcano (Lesser Antilles) since the last eruptive crisis in 1975–77: Result of a shallow magma intrusion? - Université Pierre et Marie Curie Accéder directement au contenu
Article Dans Une Revue Journal of Volcanology and Geothermal Research Année : 2011

Degassing at La Soufrière de Guadeloupe volcano (Lesser Antilles) since the last eruptive crisis in 1975–77: Result of a shallow magma intrusion?

Dégazage du volcan de La Soufrière de Guadeloupe (Petites Antilles) depuis sa dernière crise éruptive en 1975-77 : est-ce le résultat d’une intrusion magmatique à faible profondeur ?

Résumé

In the 15 years following the last crisis of phreatic type in 1975–77, the hydrothermal and seismic activity of La Soufrière de Guadeloupe has displayed an episodic behavior superimposed on a long-term decay, as inferred from seismicity and degassing, monitored through fumarolic emissions and Cl content in thermal springs. In particular, the evolution of the Cl content can be explained by a succession of magmatic gas injections into the hydrothermal system. This episodic supply of gas may be associated to the thermodynamic evolution of a batch of magma intruded at shallow depth around 1976. Progressive magma cooling, crystallization, gas exsolution and pressure buildup lead to cyclic failure of host rock around the intrusion, and episodic release of gas, with a decreasing frequency as cooling proceeds. This physical model allows to reproduce the pattern of degassing activity of La Soufrière, including the decreasing frequency of Cl pulses with time. Our preferred forward model of Cl pulses involves a magma intrusion volume in the range 0.01– 0.52 km 3 and a tensile strength of the surrounding rock in the range 0.1–0.6 MPa. These results reinforce the hypothesis of a shallow magma intrusion triggering the 1975–77 crisis and provide an explanation for the degassing and seismic activities observed until 1992.
Fichier principal
Vignette du fichier
Boichu_Et_Al_Guad_For_HAL_noJVGR_Format_final.pdf (1.14 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-01163215 , version 1 (16-06-2015)

Identifiants

Citer

Marie Boichu, Benoît Villemant, Georges Boudon. Degassing at La Soufrière de Guadeloupe volcano (Lesser Antilles) since the last eruptive crisis in 1975–77: Result of a shallow magma intrusion?. Journal of Volcanology and Geothermal Research, 2011, 203, pp.102-112. ⟨10.1016/j.jvolgeores.2011.04.007⟩. ⟨hal-01163215⟩
445 Consultations
224 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More