Remote determinations on fumarole outlet temperatures in an eruptive volcano

2015 Fiscal Year Final Research Report

• Project/Area Number: 26610181
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Geochemistry/Cosmochemistry
• Research Institution: Nagoya University
• Principal Investigator: Tsunogai Urumu 名古屋大学, 環境学研究科, 教授 (50313367)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 火山 / 噴気温度 / 噴煙 / 水素 / 同位体組成 / 火山ガス / 航空機 / 質量分析

Outline of Final Research Achievements

We used aircraft to sample the volcanic plume ejected from Sakurajima volcano, where direct measurement of fumarole outlet temperature is impractical, in order to deduce the hydrogen isotopic composition (δD) of fumarolic H2 from excess H2 in the volcanic plume and thus remotely determine the outlet temperature. We successfully estimated that the δD of the fumarolic H2 in September and December 2014 was －135 ± 13‰ and －113±11‰, respectively, and that the outlet temperature was 1,050 ± 120°C and 1,199 ± 139°C, respectively. Although the temperatures were higher than those determined using infrared (IR) remote sensing, we concluded that they are reliable estimates of the highest fumarole outlet temperatures. Combined with sampling using aircraft, remote temperature-sensing based on the δD of H2 in volcanic plumes can be widely applied to active volcanoes to determine the highest fumarole outlet temperatures.

Free Research Field

地球化学