Establishing repeating mechanism of volcanic-hydrothermal eruptions at active volcanoes

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K13998
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 17030:Human geosciences-related
• Research Institution: Yamagata University
• Principal Investigator: Imura Takumi 山形大学, 理学部, 講師 (20878524)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 山体地質 / 火山熱水系 / 火山層序

Outline of Final Research Achievements

Volcanic hydrothermal systems developed within active volcanos are as an origin of frequent and sudden phreatomagmatic and magmatic phreatomagmatic eruptions. However, their material scientific properties and spatio-temporal changes are unknown. This study focuses on Zao, Azuma, and Adatara volcanoes, which have experienced phreatomagmatic, phreatomagmatic, and magmatic eruptions at different frequencies in the last few thousand years. Based on the stratigraphy and the geologic structure of those volcanoes, we reconstructed the transition processes between phreatomagmatic and magmatic eruptions. We determined the hydrothermal conditions of the volcanoes where the eruptions occurred. By comparing the results of case studies, we found the universality and differences of volcanic hydrothermal systems and clarified the position of volcanic hydrothermal systems in the volcanic system.

Free Research Field

火成岩岩石学・地質学

Academic Significance and Societal Importance of the Research Achievements

本研究は，発生予測が難しい水蒸気噴火およびマグマ水蒸気噴火の現象理解に深く貢献する．国内における火山熱水系の研究は，噴火前後の表面現象観測の精密化，地下構造の地球物理学的イメージング，熱水流動数値モデル構築に偏っており，噴火発生場の物質科学的研究は国外の研究に後れを取っている．そこで，現在国内で行われている活動観測主体の噴火予測体制に，本研究成果が加わることで，国内の火山学および火山防災技術は革新的に発展する．本研究成果は金属鉱床学分野や地熱開発分野にも波及する．