Publication Date:
2015-05-26
Description:
Volcanic edifice collapses generate some of Earth's largest landslides. How such unloading affects the magma storage systems is important for both hazard assessment and for determining long-term controls on volcano growth and decay. Here, we present a detailed stratigraphic and petrological analysis of volcanic landslide and eruption deposits offshore Montserrat, in a subduction zone setting, sampled during IODP Expedition 340. A large (6–10 km 3 ) collapse of the Soufrière Hills volcano at ~130 ka was followed by explosive basaltic volcanism and the formation of a new basaltic volcanic centre, the South Soufrière Hills, estimated to have initiated 〈100 years after collapse. This basaltic volcanism was a sharp departure from the andesitic volcanism that characterised Soufrière Hills’ activity before the collapse. Mineral-melt thermobarometry demonstrates that the basaltic magma's transit through the crust was rapid and from mid-crustal depths. We suggest that this rapid ascent was promoted by unloading following collapse.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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