Flow‐to‐fracture transition in a volcanic mush plug may govern normal eruptions at Stromboli. Issue 23 (15th December 2016)

• Record Type: Journal Article
• Authors: Suckale, J.; Keller, T.; Cashman, K. V.; Persson, P.‐O.
• Is Part Of: Geophysical research letters. Volume 43:Issue 23(2016)
• Page Start: 12, 071
• Page End: 12, 081
• Publication Date: 2016-12-15
• Subjects: Stromboli volcano -- Strombolian eruptions -- slug -- plug -- three‐phase flow -- explosive basaltic volcanism; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL071501
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Stromboli is a model volcano for studying eruptions driven by degassing. The current paradigm posits that Strombolian eruptions represent the bursting of gas slugs ascending through melt‐filled conduits, but petrological observations show that magma at shallow depth is crystalline enough to form a three‐phase plug consisting of crystals, bubbles, and melt. We combine a 1‐D model of gas flushing a crystalline mush with a 3‐D stress model. Our results suggest that localized gas segregation establishes hot conduits of mobile magma within a stagnant plug. The plug is prone to tensile failure controlled by gas overpressure and tectonic stress, with failure most likely beneath the observed vent locations. We hence argue that Strombolian eruptions are related to plug failure rather than flow. Our proposed three‐phase model of the shallow plumbing system may provide a promising framework for integrating geophysical, petrological, and morphological observations at Stromboli and in open‐system volcanism more generally. Key Points: Rheological transition in crystalline magma creates a porous mush plug beneath Strombolian crater terrace Localized gas segregation may give rise to hot conduits of high gas flux and mobile magma through the volcanic plug Strombolian eruptions may be result of a flow‐to‐fracture transition in the mush plug induced by crustal stresses and gas overpressure