Transitions between explosive and effusive phases during the cataclysmic 2010 eruption of Merapi volcano, Java, Indonesia

Preece, K., Gertisser, R., Barclay, J., Charbonnier, S. J., Komorowski, J.-C. and Herd, R. A. (2016) Transitions between explosive and effusive phases during the cataclysmic 2010 eruption of Merapi volcano, Java, Indonesia. Bulletin of Volcanology, 78(8), 54. (doi: 10.1007/s00445-016-1046-z)

Abstract

Transitions between explosive and effusive activity are commonly observed during dome-forming eruptions and may be linked to factors such as magma influx, ascent rate and degassing. However, the interplay between these factors is complex and the resulting eruptive behaviour often unpredictable. This paper focuses on the driving forces behind the explosive and effusive activity during the well-documented 2010 eruption of Merapi, the volcano’s largest eruption since 1872. Time-controlled samples were collected from the 2010 deposits, linked to eruption stage and style of activity. These include scoria and pumice from the initial explosions, dense and scoriaceous dome samples formed via effusive activity, as well as scoria and pumice samples deposited during subplinian column collapse. Quantitative textural analysis of groundmass feldspar microlites, including measurements of areal number density, mean microlite size, crystal aspect ratio, groundmass crystallinity and crystal size distribution analysis, reveal that shallow pre- and syn-eruptive magmatic processes acted to govern the changing behaviour during the eruption. High-An (up to ∼80 mol% An) microlites from early erupted samples reveal that the eruption was likely preceded by an influx of hotter or more mafic magma. Transitions between explosive and effusive activity in 2010 were driven primarily by the dynamics of magma ascent in the conduit, with degassing and crystallisation acting via feedback mechanisms, resulting in cycles of effusive and explosive activity. Explosivity during the 2010 eruption was enhanced by the presence of a ‘plug’ of cooled magma within the shallow magma plumbing system, which acted to hinder degassing, leading to overpressure prior to initial explosive activity.

• Item Type: Articles
• Additional Information: This work has been supported by the Natural Environment Research Council (NERC) through Urgency grant NE/I029927/1. KP was funded by a NERC studentship, grant number NE/H524506/1.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Preece, Dr Katie
• Authors: Preece, K., Gertisser, R., Barclay, J., Charbonnier, S. J., Komorowski, J.-C., and Herd, R. A.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Bulletin of Volcanology
• Publisher: Springer
• ISSN: 0258-8900
• ISSN (Online): 1432-0819
• Published Online: 18 July 2016
• Copyright Holders: Copyright © 2016 The Authors
• First Published: First published in Bulletin of Volcanology 78(8): 54
• Publisher Policy: Reproduced under a Creative Commons License