Study on anisotropy of resistivity structure of Aso and Izu-Oshima volcanos

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K13631
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 17040:Solid earth sciences-related
• Research Institution: Kobe University (2019-2020); The University of Tokyo (2018)
• Principal Investigator: Minami Takuto 神戸大学, 理学研究科, 助教 (90756496)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 火山 / 比抵抗構造 / 阿蘇 / 人工電流

Outline of Final Research Achievements

This project focused on the anisotropy of the resistivity structure of the magma routes of Aso volcano, Central Kyushu, Japan, and Izu-Oshima volcano, Izu-Bonin arc, Japan, using the controlled-source electromagnetic (EM) sounding method called ACTIVE and the traditional magnetotelluric EM sounding method. We tested continuous ACTIVE monitoring in Aso volcano as well as campaign observations of ACTIVE and MT in Izu-Oshima volcano. Although the test succeeded in obtaining daily data and transferring them to laboratory, we found that a large amount of gas emission in Aso volcano makes ACTIVE monitoring for long term difficult. We are still analyzing the EM data obtained by this project, which will be completed by the following project, Grant-In-Aid for Scientific Research (B) "Observational study on hydrothermal system of Aso volcano associated with phreatic eruptions".

Free Research Field

地球電磁気学

Academic Significance and Societal Importance of the Research Achievements

これまで、火山活動のモニタリングの主役は、地震観測・全磁力観測・地殻変動観測などであり、電磁探査による比抵抗構造探査が、火山活動のモニタリングに使用されたケースは少ない。本課題では、初めて、阿蘇山のように活発な火山で連続観測を試験した。結果、火山ガスの影響で長期の観測は叶わなかったが、観測機材の機密性向上が重要な課題であることが明らかとなり、今後の電磁気学的な火山モニタリングの大きな一助となった。