Understanding of mechanisms determining eruption styles of bubble- and crystal-bearing magmas

2016 Fiscal Year Final Research Report

• Project/Area Number: 24681035
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Partial Multi-year Fund
• Research Field: Natural disaster science
• Research Institution: Hiroshima University (2014-2016); The University of Tokyo (2012-2013)
• Principal Investigator: Namiki Atsuko 広島大学, 総合科学研究科, 准教授 (20450653)
• Project Period (FY): 2012-04-01 – 2017-03-31
• Keywords: マグマ / 気泡 / 斑晶 / 粘弾性 / 脱ガス / せん断変形 / 減圧膨張 / 震動

Outline of Final Research Achievements

Magmas are the molten rocks and include bubbles and crystals. Volcanoes erupt various ways and eruption styles depend on the amount of bubbles in magmas. The bubble amount is subject to change during the magma ascent. This project aims to understand the mechanism determining the bubble amount during the magma ascent and explore a method to measure the bubble amount. Based on our model experiments, we submit equations estimating the amount of outgassing by the shear deformation and the decompression induced expansion. We also propose a model of triggered eruptions in which oscillation induces foam collapse. Finally, we find a regime of solid-like behavior of bubbly crystal-bearing fluid, in which S wave could propagate.

Free Research Field

火山学