Precise volcano monitoring by actively controlled electromagnetic signal using frequency comb
| Project/Area Number |
20H01992
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 17040:Solid earth sciences-related
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
Ogawa Yasuo 東京工業大学, 理学院, 教授 (10334525)
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| Co-Investigator(Kenkyū-buntansha) |
市原 寛 名古屋大学, 環境学研究科, 講師 (90553074)
南 拓人 神戸大学, 理学研究科, 助教 (90756496)
石須 慶一 東京工業大学, 理学院, 研究員 (80880054)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥17,810,000 (Direct Cost: ¥13,700,000、Indirect Cost: ¥4,110,000)
Fiscal Year 2022: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2021: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2020: ¥13,390,000 (Direct Cost: ¥10,300,000、Indirect Cost: ¥3,090,000)
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| Keywords | 火山モニタリング / 人工電磁探査 / 周波数コム信号 |
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| Outline of Research at the Start |
火山の噴火予知研究では、地下のマグマや熱水系の分布を解明し、その時間的な変動を監視する観測が重要である。比抵抗はマグマや熱水や粘土鉱物の分布に敏感な物理量であり、地表での電磁波の観測から、地下の比抵抗分布やその時間変動を検知することができる。地下の比抵抗分布の時間的な変動を精密に監視するには、精密に制御された人工信号を利用する電磁場観測が必須である。本研究では、精密に制御された２系統の信号系列送信し、多数の受信機で常時取得することによって、革新的な精度で火山の3次元地下構造を常時モニターするシステムを開発する。草津白根火山でこの実証実験を行う。
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| Outline of Final Research Achievements |
An electromagnetic monitoring system using precisely controlled frequency comb signals was constructed and was demonstrated at Kusatsu-Shirane volcano. Two transmitter dipoles were installed at the southern foot of the volcano, and electromagnetic receivers were placed around the peak. The distances between the transmitters and receivers are approximately 5 km. The current dipoles were in two directions one in the east-west direction and the other in the north-south direction, transmitting sine waves consisting of frequency sets with logarithmic equal intervals in the frequency range of 0.02 Hz to 4.6 Hz. By synchronising the function generator with a 10 MHz GPS signal, the transmitted signal could be repeated with high accuracy over a long period of time. The stacking method using the inverse of the noise as weights was found to be effective in extracting weak repetitive signal components from the received signals, and the response functions could be easily obtained.
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| Academic Significance and Societal Importance of the Research Achievements |
火山噴火予測研究、特に水蒸気噴火の予測のために、流体や蒸気の分布に敏感な比抵抗構造をモニタリングすることは重要である。既存の自然信号を用いる方法では、不安定な信号強度や人工ノイズの混入によって常時モニター観測が困難であった。本研究では、精密に制御された信号を繰り返し送信することによって、小さなパワーの送信源でありながら、革新的な精度で電磁気観測が可能になることを示している。同時に複数の送信源から送信することも可能であり、受信信号からテンソル情報を引き出すことができることもメリットである。この観測手法は、火山活動モニタリングの新たな方法として、今後防災研究にも大きく貢献できる可能性がある。
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Report
(4 results)
Research Products
(37 results)
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[Journal Article] 3-D resistivity imaging of the supercritical geothermal system in the Sengan geothermal region, NE Japan2022
Author(s)
Yamaya, Y., Suzuki, Y., Murata, Y., Okamoto, K., Watanabe, N., Asanuma, H., Hase, H., Ogawa, Y., Mogi, T., Ishizu, K., Uchida, T.
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Journal Title
Geothermics
Volume: 103
Pages: 102412-102412
DOI
Related Report
Peer Reviewed
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[Journal Article] Trans-crustal structural control of CO2-rich extensional magmatic systems revealed at Mount Erebus Antarctica2022
Author(s)
Hill GJ, Wannamaker PE, Maris V, Stodt JA, Kordy MA, Unsworth MJ, Bedrosian P, Wallin E, Uhlmann DF, Ogawa Y, Kyle PR
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Journal Title
Nat Commun
Volume: 13
Issue: 1
Pages: 1-10
DOI
Related Report
Peer Reviewed / Open Access / Int'l Joint Research
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[Presentation] EM-ACROSS System: Installation at the Kusatsu-Shirane Volcano, Japan2022
Author(s)
Serita, S., Ogawa, Y., Ishizu, K., Tseng, K.H., Kunitomo, T., Minami, T., Ichihara, H, Caldwell, T.G., Heise, W., Bertrand E.A.
Organizer
EMIW 2022, Cesme, Turkey
Related Report
Int'l Joint Research
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[Presentation] Crustal fault valve control of the CO2 rich Erebus volcano phonolite magmatic system, Antarctica2021
Author(s)
Graham Hill, Philip E Wannamaker, Virginia Maris, John A Stodt, Michal A Kordy, Martyn Jonathan Unsworth, Paul Bedrosian, Erin Wallin, Danny F Uhlmann, Yasuo Ogawa, Philip R Kyle
Organizer
AGU Fall Meeting 2021
Related Report
Int'l Joint Research
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[Presentation] Estimation of spatial distribution and fluid fraction of a potential supercritical geothermal reservoir by magnetotelluric data: a case study from Yuzawa geothermal field, NE Japan2021
Author(s)
Keiichi Ishizu, Yasuo Ogawa, Keishi Nunohara, Noriyoshi Tsuchiya, Masahiro Ichiki, Hideaki Hase, Wataru Kanda, Shinya Sakanaka, Yoshimori Honkura, Yuta Hino, Kaori Seki, Kuo Hsuan Tseng, Yusuke Yamaya and Toru Mogi
Organizer
AGU Fall Meeting 2021
Related Report
Int'l Joint Research
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[Presentation] Three-dimensional electrical resistivity structure beneath the back-arc side of the southern Tohoku region2021
Author(s)
Y Usui, M Uyeshima, H Hase, H Ichihara, K Aizawa, T Koyama, S Sakanaka, T Ogawa, Y Yamaya, T Nishitani, Y Ogawa, R Yoshimura, S Takakura, M Mishina, Y Morita
Organizer
第150回 地球電磁気・地球惑星圏学会 総会および講演会
Related Report
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[Presentation] Anatomy of Active Volcanic Edifice at the Kusatsu-Shirane Volcano, Japan, by Magnetotelluric's: Hydrothermal Implications for Volcanic Unrests2020
Author(s)
Kuo Hsuan Tseng, Yasuo Ogawa, Nurhasan Nurhasan, Sabri Bulent Tank, Yoshimori Honkura, Naoto Ujihara, Akihiko Terada, Yoshiya Usui, Wataru Kanda
Organizer
JpGU-AGU Joint Meeting 2020
Related Report
Int'l Joint Research
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