Improved understanding for preparation and triggering processes of eruptions involving mush-like felsic magmas-Use of diffusion profiles of multiple phenocrysts phases-

2015 Fiscal Year Final Research Report

• Project/Area Number: 25400509
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Petrology/Mineralogy/Economic geology
• Research Institution: Waseda University (2014-2015); The University of Tokyo (2013)
• Principal Investigator: Suzuki Yuki 早稲田大学, 教育・総合科学学術院, 講師 (00374918)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 新燃岳 / マグマ供給系 / マッシュ状珪長質マグマ / マグマ混合 / 噴火誘発過程 / 拡散プロファイル

Outline of Final Research Achievements

Eruption triggering process was studied for the Shinmoe-dake 2011 eruption. First, I clarified two points; 1) the eruption was triggered by the remobilization of mush-like felsic magma through injection of high temperature magma, and 2) the plumbing system of the two magmas that formed the final product (mixed magmas). Second, I discussed timescale from magma mixing to eruption and their correlation with eruption timing, focusing on sub-Plinian events in the climactic stage in the 2011 eruption. For this purpose, I examined diffusion profiles of magnetites originated from the felsic magma. Because the sub-Plinian events occurred intermittently, I took intermittent injection of high temperature magma into account. Due to the importance of eruption timing in this study, I newly clarified the boundary between the first and second sub-Plinian deposit by using groundmass textures of the juvenile material.

Free Research Field

火山岩石学