Updated on 2024/07/28

Information

 

写真a

 
GESHI NOBUO
 
Organization
Faculty of Science Department of Earth and Planetary Sciences Professor
School of Sciences Department of Earth and Planetary Sciences(Joint Appointment)
Graduate School of Sciences Department of Earth and Planetary Sciences(Joint Appointment)
Title
Professor
Contact information
メールアドレス
Profile
I promote the study of the subsurface behavior of magmas that drives volcanic eruptions, using the combinative approaches of geological and petrological methods. How magma rises in the crust forms magma reservoirs, what triggers magma accumulated in magma reservoirs to start rising toward the surface, and what kind of dynamic balance is required for the formation of magmatic conduit. The formation processes of volcanic conduits and calderas caused by the collapse of magma chambers are also the subject of my research. I also study the transition mechanism of explosive eruptions by analyzing the microstructure and chemical composition of volcanic ash and other eruptive products. I am also studying the history of eruption activities of volcanoes using the geological analysis of the lithofacies and stratigraphy of the volcanic products. Though I have studied many volcanoes in Japan and international, recently I have studied mainly the volcanoes and volcanic fields in the Kyushu area, such as Sakurajima and Aira Caldera. Recently, I have been introducing various automated analysis methods for the volcanic ejecta and volcanic outcrops.
External link

Degree

  • PhD in Science

Research Interests・Research Keywords

  • Research theme:Research of Volcanic activity and eruption mechanism

    Keyword:volcano, eruption, magma,

    Research period: 2024.4

Awards

  • 日本火山学優秀学術賞

    2017.5   非特定営利活動法人日本火山学会   マグマ上昇・貫入・噴火過程とカルデラ形成過程の地質学的研究

  • 日本火山学会優秀論文賞

    2007.5   非特定営利活動法人日本火山学会   鹿児島県口永良部島火山最近3万年間の噴火活動

  • 日本火山学研究奨励賞

    2004.5   非特定営利活動法人日本火山学会   マグマ供給系の構造発達とマグマ進化

Papers

  • Voluminous magma formation for the 30-ka Aira caldera-forming eruption in SW Japan: contributions of crust-derived felsic and mafic magmas

    Ayumu Nishihara, Yoshiyuki Tatsumi, Katsuya Kaneko, Jun-Ichi Kimura, Qing Chang, Nobuo Geshi, Takashi Miyazaki, Bogdan Stefanov Vaglarov, Hironobu Hinata, Keiko Suzuki-Kamata

    Frontiers in Earth Science   11   2024.1

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    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.3389/feart.2023.1283844

  • Redox state of magma recorded in volcanic glass from an ash-forming eruption at Bromo volcano, Indonesia: Insights into the degassing process

    Takahiro Miwa, Hidemi Ishibashi, Ryunosuke Kazahaya, Satoshi Okumura, Masato Iguchi, Genji Saito, Atsushi Yasuda, Nobuo Geshi, Hiroyuki Kagi

    Bulletin of Volcanology   85 ( 9 )   2023.8

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    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s00445-023-01660-1

  • Importance of long-term shallow degassing of basaltic magma on the genesis of massive felsic magma reservoirs: A case study of Aso caldera, Kyushu, Japan

    Isoji Miyagi, Hideo Hoshizumi, Taichi Suda, Genji Saito, Yasuo Miyabuchi, Nobuo Geshi

    Journal of Petrology   2023.2

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    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1093/petrology/egad009

  • Influence of hydrothermal recharge on the evolution of eruption styles and hazards during the 2018–2019 activity at Kuchinoerabujima Volcano, Japan

    74 ( 1 )   2022.12

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    <title>Abstract</title>The activity of the 2018<bold>–</bold>2019 eruption of Kuchinoerabujima Volcano in Japan changed from continuous ejection of ash-laden plumes between October 21 and the middle of December, to intermittent explosive activity accompanied by several pyroclastic density currents until January 2019. To understand the behaviors of magma and hydrothermal fluid that controlled the eruptive sequence, we carried out component analysis, X-ray diffractometry, and leachate analysis for ash samples. The proportion of non-altered volcanic ash particles is ~ 15&#37; in the earlier phase, then it decreased to less than 10&#37; in the later explosive phase. Accordingly, the mineral assemblage of the volcanic ash samples changed from plagioclase-dominant to sulfate minerals-dominant. Concentration of SO42− and Cl/SO4 values of the ash-leachates decreased toward the later activity. These results indicate that the proportion of fresh volcanic rocks decreased and sulfuric acid fluid-derived sulfate minerals increased toward the later activities. Consequently, the 2018<bold>–</bold>2019 eruption at Kuchinoerabujima Volcano changed from magmatic activity to phreatomagmatic activity. Weak glowing of the crater was observed during the magmatic activity, indicating the volcanic conduit was hot enough to dry up the sub-volcanic hydrothermal system. The following phreatomagmatic activity indicates that the hydrothermal fluid recharged after the magmatic eruption phase. Recharge of the hydrothermal fluid likely caused the variation of the eruption style, and is a process that may control the evolution of hazards during future eruption scenarios at similar active volcanoes in Japan and worldwide.


    <bold>Graphical Abstract</bold>

    DOI: 10.1186/s40623-022-01580-y

  • Long-term change of the eruption activities of Sakurajima volcano, Japan, inferred from the fallout tephra deposits

    Nobuo Geshi, Hideto Naruo

    Frontiers in Earth Science   10   2022.11

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    DOI: 10.3389/feart.2022.988373

  • Volcanotectonics: the tectonics and physics of volcanoes and their eruption mechanics

    Bulletin of Volcanology   84 ( 8 )   2022.8

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    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s00445-022-01582-4

  • Eruptive dynamics and fragmentation mechanisms during cyclic Vulcanian activity at Sakurajima volcano (Japan): Insights from ash texture analysis

    Pietro Gabellini, Raffaello Cioni, Nobuo Geshi, Marco Pistolesi, Takahiro Miwa, Giorgio Lacanna, Maurizio Ripepe

    Journal of Volcanology and Geothermal Research   428   107582 - 107582   2022.8

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    DOI: 10.1016/j.jvolgeores.2022.107582

  • Shallow crystallization of eruptive magma inferred from volcanic ash microtextures: a case study of the 2018 eruption of Shinmoedake volcano, Japan Reviewed

    Keiko Matsumoto, Nobuo Geshi

    Bulletin of Volcanology   83 ( 5 )   2021.5

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s00445-021-01451-6

  • Automatic onsite imaging of volcanic ash particles with VOLCAT: Towards quasi-real-time eruption style monitoring

    Takahiro Miwa, Nobuo Geshi, Jun'ichi Itoh, Toshikazu Tanada, Masato Iguchi

    Journal of Volcanology and Geothermal Research   107267 - 107267   2021.4

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    DOI: 10.1016/j.jvolgeores.2021.107267

  • Volcanological challenges to understanding explosive large-scale eruptions Reviewed

    Nobuo Geshi

    Earth, Planets and Space   72 ( 1 )   2020.12

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    DOI: 10.1186/s40623-020-01222-1

  • Magmatic overpressures, volatile exsolution and potential explosivity of fissure eruptions inferred via dike aspect ratios Reviewed

    Nobuo Geshi, John Browning, Shigekazu Kusumoto

    Scientific Reports   10 ( 1 )   2020.12

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    DOI: 10.1038/s41598-020-66226-z

  • 第5回国際火山地質研究集会報告

    下司信夫, 宮縁育夫, 後藤聡・Linus Anye NCHE

    火山   65 ( 2 )   59 - 66   2020.6

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    Language:Japanese  

    DOI: 10.18940/kazan.65.2_59

  • Accumulation of rhyolite magma and triggers for a caldera-forming eruption of the Aira Caldera, Japan Reviewed

    Nobuo Geshi, Ikuko Yamada, Keiko Matsumoto, Ayumu Nishihara, Isoji Miyagi

    Bulletin of Volcanology   82 ( 6 )   2020.6

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    DOI: 10.1007/s00445-020-01384-6

  • Heat source of the 2014 phreatic eruption of Mount Ontake, Japan Reviewed

    82 ( 4 )   2020.4

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    © 2020, The Author(s). We present petrological evidence of the shallow magmatic processes that may have supplied heat and gas to the eruption of Mount Ontake, Japan, on 27 September 2014, which resulted in 63 fatalities. Ash from the eruption comprises primarily hydrothermally altered, white-toned rock fragments. However, the ash contains trace amounts (< 0.7 wt&#37;) of vitreous less-altered particles (LAPs), which are only altered on their surfaces, suggesting rapid ascent through the hydrothermal system. The LAPs are classified into two categories: “glassy” and “crystalline.” Glassy LAPs comprise high-silica rhyolitic glass (74–83 wt&#37; SiO2) with rounded quartz, chalcedony-free vesicles, and reversely zoned plagioclase (cores = 47 mol&#37; An; rims = 70 mol&#37; An), indicating magma re-heating. Crystalline LAPs have a groundmass-like texture that suggests eutectic crystallization at shallow depths. Thermodynamic calculations indicate that the pre-eruptive temperatures of the glassy and crystalline LAPs were 700–1300 °C and ~ 700 °C, respectively, and that the storage depth was < 4 km (pressure < 100 MPa). The observed petrological features suggest that the LAPs were sourced from a magma recently intruded at shallow depths. Although crustal deformation (i.e., the volume change associated with magmatic intrusion) was insignificant prior to the 2014 eruption, a clear signature of crustal deformation was observed in 2007, the source of which was located 3 km below the summit. We suggest that the magma that was intruded 3 km below the summit in 2007 supplied the heat and gas for the 2014 phreatic eruption.

    DOI: 10.1007/s00445-020-1358-x

  • A roadmap for amphibious drilling at the Campi Flegrei caldera: Insights from a MagellanPlus workshop Reviewed

    Scientific Drilling   26   29 - 46   2019.12

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    DOI: 10.5194/sd-26-29-2019

  • Eruption age of the Haruna Futatsudake Pumice (Hr-FP), central Japan, by radiocarbon wiggle matching with special reference to a 14C dataset developed from a Japanese tree Reviewed

    Mitsuru Okuno, Toshio Nakumura, Minoru Sakamoto, Shinya Yatsuzuka, Teruki Oikawa, Nobuo Geshi, Yasuharu Hoshino, Toshihiko Takahashi

    Quaternary International   527   29 - 33   2019.8

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.quaint.2018.12.023

  • Shift from magmatic to phreatomagmatic explosions controlled by the lateral evolution of a feeder dike in the Suoana-Kazahaya eruption, Miyakejima Volcano, Japan Reviewed

    Earth and Planetary Science Letters   511   177 - 189   2019.4

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    DOI: 10.1016/j.epsl.2019.01.038

  • Pyroclastic density currents associated with the 2015 phreatomagmatic eruption of the Kuchinoerabujima volcano Reviewed

    Earth, Planets and Space   70 ( 1 )   2018.12

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    DOI: 10.1186/s40623-018-0881-x

  • Pyroclastic density currents associated with the 2015 phreatomagmatic eruption of the Kuchinoerabujima volcano Reviewed

    Geshi Nobuo, Itoh Jun'ichi

    EARTH PLANETS AND SPACE   70 ( 1 )   2018.7

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    Pyroclastic density currents associated with the 2015 phreatomagmatic eruption of the Kuchinoerabujima volcano

    DOI: 10.1186/s40623-018-0881-x

  • Thermal interactions of the AD79 Vesuvius pyroclastic density currents and their deposits at Villa dei Papiri (Herculaneum archaeological site, Italy) Reviewed

    G. Giordano, E. Zanella, M. Trolese, C. Baffioni, A. Vona, C. Caricchi, A. A. De Benedetti, S. Corrado, C. Romano, R. Sulpizio, N. Geshi

    Earth and Planetary Science Letters   490   180 - 192   2018.5

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    DOI: 10.1016/j.epsl.2018.03.023

  • Distribution and mass of tephra-fall deposits from volcanic eruptions of Sakurajima Volcano based on posteruption surveys Reviewed

    Masayuki Oishi, Kuniaki Nishiki, Nobuo Geshi, Ryuta Furukawa, Yoshihiro Ishizuka, Teruki Oikawa, Takahiro Yamamoto, Futoshi Nanayama, Akiko Tanaka, Akinari Hirota, Takahiro Miwa, Yasuo Miyabuchi

    Bulletin of Volcanology   80 ( 4 )   2018.4

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    DOI: 10.1007/s00445-018-1215-3

  • Salt shell fallout during the ash eruption at the Nakadake crater, Aso volcano, Japan: evidence of an undergrounds hydrothermal system surrounding the erupting vent

    Shinohara Hiroshi, Geshi Nobuo, Yokoo Akihiko, Ohkura Takahiro, Terada Akihiko

    Earth, Planets and Space   70 ( 70 )   2018.3

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    Salt shell fallout during the ash eruption at the Nakadake crater, Aso volcano, Japan: evidence of an undergrounds hydrothermal system surrounding the erupting vent

    DOI: 10.1186/s40623-018-0798-4

  • Tsunami deposits associated with the 7.3 ka caldera-forming eruption of the Kikai Caldera, insights for tsunami generation during submarine caldera-forming eruptions Reviewed

    Nobuo Geshi, Fukashi Maeno, Shojiro Nakagawa, Hideto Naruo, Tetsuo Kobayashi

    Journal of Volcanology and Geothermal Research   347   221 - 233   2017.11

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    DOI: 10.1016/j.jvolgeores.2017.09.015

  • The 1914 Taisho eruption of Sakurajima volcano: stratigraphy and dynamics of the largest explosive event in Japan during the twentieth century Reviewed

    A. Todde, R. Cioni, M. Pistolesi, N. Geshi, C. Bonadonna

    Bulletin of Volcanology   79 ( 10 )   2017.10

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    DOI: 10.1007/s00445-017-1154-4

  • Potential impacts of tephra fallout from a large-scale explosive eruption at Sakurajima volcano, Japan Reviewed

    S. Biass, A. Todde, R. Cioni, M. Pistolesi, N. Geshi, C. Bonadonna

    Bulletin of Volcanology   79 ( 10 )   2017.10

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    DOI: 10.1007/s00445-017-1153-5

  • Steady subsidence of a repeatedly erupting caldera through InSAR observations: Aso, Japan Reviewed

    Adriano Nobile, Valerio Acocella, Joel Ruch, Yosuke Aoki, Sven Borgstrom, Valeria Siniscalchi, Nobuo Geshi

    Bulletin of Volcanology   79 ( 5 )   2017.5

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    DOI: 10.1007/s00445-017-1112-1

  • Large-volume lateral magma transport from the Mull volcano: An insight to magma chamber processes Reviewed

    Osamu Ishizuka, Rex N. Taylor, Nobuo Geshi, Nobutatsu Mochizuki

    Geochemistry, Geophysics, Geosystems   18 ( 4 )   1618 - 1640   2017.4

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    DOI: 10.1002/2016GC006712

  • Volcanic gas composition changes during the gradual decrease of the gigantic degassing activity of Miyakejima volcano, Japan, 2000-2015 Reviewed

    Hiroshi Shinohara, Nobuo Geshi, Nobuo Matsushima, Genji Saito, Ryunosuke Kazahaya

    Bulletin of Volcanology   79 ( 2 )   2017.2

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    DOI: 10.1007/s00445-017-1105-0

  • Special issue "the phreatic eruption of Mt. Ontake volcano in 2014" the Phreatic Eruption of Mt. Ontake Volcano in 2014 5. Volcanology Reviewed

    Koshun Yamaoka, Nobuo Geshi, Takeshi Hashimoto, S. E. Ingebritsen, Teruki Oikawa

    Earth, Planets and Space   68 ( 1 )   2016.12

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    DOI: 10.1186/s40623-016-0548-4

  • Estimation of total discharged mass from the phreatic eruption of Ontake Volcano, central Japan, on September 27, 2014 Reviewed

    Shinji Takarada, Teruki Oikawa, Ryuta Furukawa, Hideo Hoshizumi, Jun'Ichi Itoh, Nobuo Geshi, Isoji Miyagi

    Earth, Planets and Space   68 ( 1 )   2016.12

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1186/s40623-016-0511-4

  • Phreatomagmatic and water-influenced Strombolian eruptions of a small-volume parasitic cone complex on the southern ringplain of Mt. Ruapehu, New Zealand: Facies architecture and eruption mechanisms of the Ohakune Volcanic Complex controlled by an unstable fissure eruption Reviewed

    Journal of Volcanology and Geothermal Research   327   99 - 115   2016.11

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    DOI: 10.1016/j.jvolgeores.2016.07.005

  • Orientation of the eruption fissures controlled by a shallow magma chamber in Miyakejima Reviewed

    Nobuo Geshi, Teruki Oikawa

    Frontiers in Earth Science   4   2016.11

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    DOI: 10.3389/feart.2016.00099

  • Conditions for long-lasting gas eruptions: The 2013 event at Fiumicino International Airport (Rome, Italy) Reviewed

    G. Giordano, M. L. Carapezza, G. Della Monica, M. Todesco, P. Tuccimei, G. Carlucci, A. A. De Benedetti, A. Gattuso, C. Lucchetti, M. Piersanti, M. Ranaldi, L. Tarchini, N. M. Pagliuca, T. Ricci, S. Facchini, F. D'Ambrosio, M. Misuraca, A. Bonamico, N. Geshi

    Journal of Volcanology and Geothermal Research   325   119 - 134   2016.10

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    DOI: 10.1016/j.jvolgeores.2016.06.020

  • Conduit enlargement during the precursory Plinian eruption of Aira Caldera, Japan Reviewed

    Nobuo Geshi, Yasuo Miyabuchi

    Bulletin of Volcanology   78 ( 9 )   2016.9

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    DOI: 10.1007/s00445-016-1057-9

  • Lava flow hazards-An impending threat at Miyakejima volcano, Japan Reviewed

    Annalisa Cappello, Nobuo Geshi, Marco Neri, Ciro Del Negro

    Journal of Volcanology and Geothermal Research   308   1 - 9   2015.12

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    DOI: 10.1016/j.jvolgeores.2015.10.005

  • Progressive mixed-magma recharging of Izu-Oshima volcano, Japan: A guide to magma chamber volume Reviewed

    Osamu Ishizuka, Rex N. Taylor, Nobuo Geshi, Teruki Oikawa, Yoshihisa Kawanabe, Itaru Ogitsu

    Earth and Planetary Science Letters   430   19 - 29   2015.7

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    DOI: 10.1016/j.epsl.2015.08.004

  • Migration of a volcanic front inferred from K-Ar ages of late Miocene to Pliocene volcanic rocks in central Japan Reviewed

    Hitomi Nakamura, Teruki Oikawa, Nobuo Geshi, Akikazu Matsumoto

    Island Arc   23 ( 3 )   236 - 250   2014.9

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    DOI: 10.1111/iar.12073

  • Long-distance magma transport from arc volcanoes inferred from the submarine eruptive fissures offshore Izu-Oshima volcano, Izu-Bonin arc Reviewed

    Osamu Ishizuka, Nobuo Geshi, Yoshihisa Kawanabe, Itaru Ogitsu, Rex N. Taylor, Taqumi Tuzino, Izumi Sakamoto, Kohsaku Arai, Shun Nakano

    Journal of Volcanology and Geothermal Research   285   1 - 17   2014.9

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    DOI: 10.1016/j.jvolgeores.2014.08.006

  • Dynamic feeder dyke systems in basaltic volcanoes: The exceptional example of the 1809 Etna eruption (Italy) Reviewed

    Nobuo Geshi, Marco Neri

    Frontiers in Earth Science   2 ( Jul )   2014.7

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    DOI: 10.3389/feart.2014.00013

  • Evaluating volumes for magma chambers and magma withdrawn for caldera collapse Reviewed

    Nobuo Geshi, Joel Ruch, Valerio Acocella

    Earth and Planetary Science Letters   396   107 - 115   2014.6

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    DOI: 10.1016/j.epsl.2014.03.059

  • The spectrum of basaltic feeder systems from effusive lava eruption to explosive eruption at Miyakejima volcano, Japan Reviewed

    Nobuo Geshi, Teruki Oikawa

    Bulletin of Volcanology   76 ( 3 )   1 - 14   2014.3

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    DOI: 10.1007/s00445-014-0797-7

  • Short time scales of magma-mixing processes prior to the 2011 eruption of Shinmoedake volcano, Kirishima volcanic group, Japan Reviewed

    Akihiko Tomiya, Isoji Miyagi, Genji Saito, Nobuo Geshi

    Bulletin of Volcanology   75 ( 10 )   1 - 19   2013.10

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s00445-013-0750-1

  • Temporal variation in volcanic ash texture during a vulcanian eruption at the sakurajima volcano, Japan Reviewed

    Takahiro Miwa, Nobuo Geshi, Hiroshi Shinohara

    Journal of Volcanology and Geothermal Research   260   80 - 89   2013.6

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.jvolgeores.2013.05.010

  • Preface

    NAKADA Setsuya, UKAWA Motoo, NEWHALL Christopher G., MCNUTT Stephen R., WRIGHT Thomas L., ICHIHARA Mie, GESHI Nobuo

    Earth, planets and space   65 ( 6 )   473 - 473   2013.6

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    Preface

    DOI: 10.5047/eps.2013.06.002

  • Aspect ratios and magma overpressures of non-feeder dikes observed in the Miyake-jima volcano (Japan), and fracture toughness of its upper part Reviewed

    Shigekazu Kusumoto, Nobuo Geshi, Agust Gudmundsson

    Geophysical Research Letters   40 ( 6 )   1065 - 1068   2013.3

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    DOI: 10.1002/grl.50284

  • What do we know about calderas? Reviewed

    V. Alerio Acocella, Adelina Geyer, Nobuo Geshi

    Eos   94 ( 2 )   22   2013.1

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    DOI: 10.1002/2013EO020010

  • AMS radiocarbon dating of wood trunks in the pumiceous deposits of the Kikai-Akahoya eruption in Yakushima Island, SW Japan Reviewed

    Mitsuru Okuno, Toshio Nakamura, Nobuo Geshi, Katsuhiko Kimura, Yoko Saito-Kokubu, Tetsuo Kobayashi

    Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms   294   602 - 605   2013.1

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    DOI: 10.1016/j.nimb.2012.05.015

  • Inverse modeling for estimating fluid-overpressure distributions and stress intensity factors from an arbitrary open-fracture geometry Reviewed

    Shigekazu Kusumoto, Agust Gudmundsson, Trine H. Simmenes, Nobuo Geshi, Sonja L. Philipp

    Journal of Structural Geology   46   92 - 98   2013.1

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.jsg.2012.10.004

  • From structure- to erosion-controlled subsiding calderas: evidence thresholds and mechanics Reviewed

    Nobuo Geshi, Valerio Acocella, Joel Ruch

    BULLETIN OF VOLCANOLOGY   74 ( 6 )   1553 - 1567   2012.8

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    DOI: 10.1007/s00445-012-0617-x

  • Kinematic analysis of vertical collapse on volcanoes using experimental models time series Reviewed

    J. Ruch, V. Acocella, N. Geshi, A. Nobile, F. Corbi

    JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH   117   2012.7

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1029/2012JB009229

  • Decompression rate of magma at fragmentation: Inference from broken crystals in pumice of vulcanian eruption Reviewed

    Takahiro Miwa, Nobuo Geshi

    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH   227   76 - 84   2012.5

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    DOI: 10.1016/j.jvolgeores.2012.03.003

  • Effects of mechanical layering of host rocks on dike growth and arrest Reviewed

    Nobuo Geshi, Shigekazu Kusumoto, Agust Gudmundsson

    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH   223   74 - 82   2012.4

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    DOI: 10.1016/j.jvolgeores.2012.02.004

  • Growth of phreatomagmatic explosion craters: A model inferred from Suoana crater in Miyakejima Volcano, Japan Reviewed

    Nobuo Geshi, Karoly Nemeth, Teruki Oikawa

    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH   201 ( 1-4 )   30 - 38   2011.4

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    DOI: 10.1016/j.jvolgeores.2010.11.012

  • 特集号「日本列島形成史と次世代パラダイム(Part III)」表層地質からマントル対流起動論へ : 巻頭言

    磯崎 行雄, 丸山 茂徳, 柳井 修一, 笠原 順三, 下司 信夫, 佐野 修

    地學雜誌   120 ( 1 )   1 - 3   2011.2

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    Language:Japanese  

    DOI: 10.5026/jgeography.120.1

  • 特集号「日本列島形成史と次世代パラダイム (Part II)」表層地質からマントル対流起動論へ : 巻頭言

    丸山 茂徳, 磯崎 行雄, 柳井 修一, 下司 信夫, 佐野 修, 笠原 順三

    地學雜誌   119 ( 6 )   959 - 962   2010.12

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    DOI: 10.5026/jgeography.119.959

  • 特集号「日本列島形成史と次世代パラダイム (Part I)」 : 巻頭言

    磯崎 行雄, 丸山 茂徳, 柳井 修一, 下司 信夫, 佐野 修, 笠原 順三

    地學雜誌   119 ( 2 )   187 - 189   2010.4

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    DOI: 10.5026/jgeography.119.187

  • Geometric difference between non-feeder and feeder dikes Reviewed

    Nobuo Geshi, Shigekazu Kusumoto, Agust Gudmundsson

    GEOLOGY   38 ( 3 )   195 - 198   2010.3

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    DOI: 10.1130/G30350.1

  • 特集号「海洋地殻内熱水循環と地下微生物圏の相互作用」 : はじめに

    石橋 純一郎, 浦辺 徹郎, 砂村 倫成, 高井 研, 丸山 茂徳, 下司 信夫, 笠原 順三

    地學雜誌   118 ( 6 )   1021 - 1026   2009.12

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    DOI: 10.5026/jgeography.118.1021

  • 屋久島を覆った約7300年前の幸屋火砕流堆積物の流動・堆積機構

    下司 信夫

    地學雜誌   118 ( 6 )   1254 - 1260   2009.12

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    A large pyroclastic eruption occurred around 7.3 ka from the Kikai caldera about 30 km north of Yakushima Island. Its pyroclastic flow and fall deposits covered the entire area of Yakushima Island and may have influenced the evolution of unique floras and faunas of Yakushima Island.  Detailed field survey revealed that the Koya pyroclastic flow deposit spread from NW to SE, covering almost the entire area of Yakushima. A part of the southern coastal area remained from the pyroclastic flow due to local alignment of topographic ridges and valleys, which acted as barriers to the pyroclastic flows. Possible tsunami deposits associated with the Kikai-Akahoya eruption were discovered in the area below ca. 50 m above sea level along the northern coasts of Yakushima and Kuchinoerabujima Islands.

    DOI: 10.5026/jgeography.118.1254

  • Asymmetric growth of collapsed caldera by oblique subsidence during the 2000 eruption of Miyakejima, Japan Reviewed

    Nobuo Geshi

    EARTH AND PLANETARY SCIENCE LETTERS   280 ( 1-4 )   149 - 158   2009.4

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    DOI: 10.1016/j.epsl.2009.01.027

  • Phreatomagmatic eruptions associated with the caldera collapse during the Miyakejima 2000 eruption, Japan Reviewed

    Nobuo Geshi, Teruki Oikawa

    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH   176 ( 4 )   457 - 468   2008.10

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    DOI: 10.1016/j.jvolgeores.2008.04.013

  • 岩手・宮城内陸地震(2008年6月14日)による地変(速報) Reviewed

    田村 俊和, 稲崎 富士, 下司 信夫, 下川 浩一, 須貝 俊彦, 中島 和敏

    地學雜誌   117 ( 4 )   697 - 703   2008.9

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    &emsp;A strong earthquake of M7.2 (MW6.7-6.9) occurred on 14 June 2008 in the north-central part of Northeastern Japan. It was named the Iwate-Miyagi Nairiku Earthquake in 2008. Several seismic models show a 25-30km long reverse fault in the NNE-SSW direction and a westward inclination. Although some geological thrusts with a similar trend are known, as shown in Fig. 1, none of them has been recognized as an active fault. Surface faults associated with the earthquake were found at several points along the geological thrusts. The quake induced many mass-movements in the mountainous and hilly area, which is composed mostly of Neogene to Pleistocene volcaniclastic rocks (Fig. 1), near the seismic fault and particularly on the western side (upper block). Most of the damage caused by the earthquake was closely connected to mass-movements. &emsp;A large-scale block glide amounting to about 7&times;107m3 in the volume of dislocated mass (Figs. 2, 3) occurred in the northern half of the pre-existing landslide area composed of poorly-consolidated pyroclastic flow deposits with a welded cap around 5Ma (Np3 in Fig. 1). The almost horizontal slip surface of the glide is considered to have been formed in the underlying lacustrine beds. A large collapse, occurring at a slope on which snow remained on Kurikoma Volcano, composed of Quaternary andesitic lavas and pyroclastics (Qm2 in Fig. 1), formed a debris flow (Fig. 4) which buried a lodge at Komanoyu Spa. Many landslides checked river channels. One of them was observed at Ogawara, where a slide of a spur composed of Pleistocene pyroclastic deposits checked the Ichihasama River (Fig. 5). The collapse of Matsurube Bridge, a three-span 95 m-long bridge over a tributary of the Iwai River, was also entirely caused by a landslide at the north-facing slope of a narrow ridge (Fig. 6). A surface fault appeared in rice fields at Mochikorobashi on the side of a tributary of the Koromo River (Fig. 7). The trace of the water's edge and lines of planted rice indicate a co-seismic uplift and a right-lateral offset with a clockwise turn of the trend (Fig. 8).

    DOI: 10.5026/jgeography.117.697

  • The magmatic plumbing of the submarine Hachijo NW volcanic chain, Hachijojima, Japan: Long-distance magma transport? Reviewed

    Osamu Ishizuka, Nobuo Geshi, Jun'ichi Itoh, Yoshihisa Kawanabe, Taqumi TuZino

    Journal of Geophysical Research: Solid Earth   113 ( 8 )   2008.8

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    DOI: 10.1029/2007JB005325

  • Vertical and lateral propagation of radial dikes inferred from the flow-direction analysis of the radial dike swarm in Komochi Volcano, Central Japan Reviewed

    Nobuo Geshi

    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH   173 ( 1-2 )   122 - 134   2008.6

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    DOI: 10.1016/j.jvolgeores.2008.01.001

  • The magmatic plumbing of the submarine Hachijo NW volcanic chain, Hachijojima, Japan: Long-distance magma transport? Reviewed

    Osamu Ishizuka, Nobuo Geshi, Jun'ichi Itoh, Yoshihisa Kawanabe, Taqumi TuZino

    JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH   113 ( B8 )   2008.6

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    DOI: 10.1029/2007JB005325

  • Size and volume evaluation of the caldera collapse on Piton de la Fournaise volcano during the April 2007 eruption using ASTER stereo imagery Reviewed

    Minoru Urai, Nobuo Geshi, Thomas Staudacher

    GEOPHYSICAL RESEARCH LETTERS   34 ( 22 )   2007.11

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    DOI: 10.1029/2007GL031551

  • The magmatic plumbing of the submarine volcanic chain of an oceanic island arc volcano: Long distance lateral magma transport? Reviewed

    O. Ishizuka, N. Geshi, J. Itoh, Y. Kawanabe, T. Tsujino

    GEOCHIMICA ET COSMOCHIMICA ACTA   71 ( 15 )   A431 - A431   2007.8

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  • Discrete plumbing systems and heterogeneous magma sources of a 24 km(3) off-axis lava field on the western flank of East Pacific Rise, 14 degrees S. Reviewed

    Nobuo Geshi, Susumu Umino, Hidenori Kumagai, John M. Sinton, Scott M. White, Kiyoyuki Kisimoto, Thomas W. Hilde

    EARTH AND PLANETARY SCIENCE LETTERS   258 ( 1-2 )   61 - 72   2007.6

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    DOI: 10.1016/j.epsl.2007.03.019

  • Implication of the temporal sulphur isotopic variation during the 2000 eruption of Miyakejima Volcano, Japan

    IMAI AKIRA, GESHI NOBUO, SHIMANO TAKETO, NAKADA SETSUYA

    The Island arc   16 ( 1 )   83 - 92   2007.3

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    Implication of the temporal sulphur isotopic variation during the 2000 eruption of Miyakejima Volcano, Japan
    The variation of sulphur isotopic composition during the 2000 eruption of the Miyakejima Volcano was examined in order to monitor the temporal change of the volcanic activity. The delta S-34 values of water-soluble sulphate leached from volcanic ash effused during intermittent eruptions from July to September 2005 range from +5 to +11 parts per thousand with a fluctuation of ca 3 parts per thousand within a single eruption. The delta S-34 value of sulphuric acid mist collected with 'Cu-metal trap' placed on the flank of the volcano from December 2000 to January 2001 is +6.2 parts per thousand. These sulphur isotopic compositions of sulphate, which were isotopically equilibrated in the subvolcanic hydrothermal system, indicate that the temperature of the hydrothermal system beneath the caldera increased after the period of intermittent phreatic and phreatomagmatic eruptions. Then, the delta S-34 value of sulphuric acid trapped from January to March 2001 was +9.0 parts per thousand and the delta S-34 value of water-soluble sulphate on volcanic ash emitted with minor eruption in May 2001 was +11.0 parts per thousand, suggesting a decrease in temperature of the subvolcanic hydrothermal system.

    DOI: 10.1111/j.1440-1738.2007.00549.x

  • はじめに : 特集号『水 ; 地球中心核から大気まで』

    丸山 茂徳, 江口 孝雄, 笠原 順三, 下司 信夫, 松本 淳, 松山 洋, 山川 修治

    地學雜誌   116 ( 1 )   1 - 6   2007.2

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    DOI: 10.5026/jgeography.116.1

  • Structural development of dike swarms controlled by the change of magma supply rate: the cone sheets and parallel dike swarms of the Miocene Otoge igneous complex, Central Japan Reviewed

    N Geshi

    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH   141 ( 3-4 )   267 - 281   2005.3

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    DOI: 10.1016/j.jvolgeores.2004.11.002

  • 愛知県設楽地域に分布する中期中新世大峠火山岩体の構造発達過程とそのマグマ供給系

    下司 信夫

    地質學雜誌   109 ( 10 )   580 - 594   2003.10

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    設楽火山岩体の一部を構成する大峠火山岩体の形成過程は,コールドロン形成期の火砕噴火のステージと,後コールドロン期の岩脈・シート群の貫入のステージに分けられる後コールドロン期における貫入岩体の形成は,大峠コーンシート群の形成から設楽中央岩脈群の形成に漸移し,ほぼ同時期に大峠ストック群が形成された大峠火山岩体は主にアルカリ苦鉄質岩からなり,少量のカルクアルカリ質デイサイトを伴う全岩組成の時間変化は,後コールドロン期の初期に発生した浅部のマグマ溜りへの未分化な苦鉄質マグマの再供給によって後コールドロン期の貫入岩体が形成されたことを示唆する

    DOI: 10.5575/geosoc.109.580

  • Caldera collapse during the 2000 eruption of Miyakejima Volcano, Japan Reviewed

    N Geshi, T Shimano, T Chiba, S Nakada

    BULLETIN OF VOLCANOLOGY   64 ( 1 )   55 - 68   2002.3

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    DOI: 10.1007/s00445-001-0184-z

  • Melt segregation by localized shear deformation and fracturing during crystallization of magma in shallow intrusions of the Otoge volcanic complex, central Japan Reviewed

    N Geshi

    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH   106 ( 3-4 )   285 - 300   2001.5

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    DOI: 10.1016/S0377-0273(00)00271-7

  • Fractionation and magma mixing within intruding dike swarm: evidence from the Miocene Shitara-Otoge igneous complex, central Japan Reviewed

    N Geshi

    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH   98 ( 1-4 )   127 - 152   2000.5

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    DOI: 10.1016/S0377-0273(99)00188-2

  • 自然硫黄のスピニフェックス組織:北海道知床硫黄山の溶融硫黄流噴火の冷却生成物

    今井 亮, 下司 信夫

    49 ( 2 )   99 - 104   1999.6

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    DOI: 10.1111/j.1751-3928.1999.tb00035.x

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Books

  • 火山のきほん

    下司信夫, 斎藤雨梟( Role: Joint author)

    誠文堂新光社  2023.9 

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  • 火山全景: 写真でめぐる世界の火山地形と噴出物

    下司 信夫, 白尾 元理

    誠文堂新光社  2017.8 

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    Responsible for pages:総ページ数:191   Language:Others  

  • 日本の地形・地質―見てみたい大地の風景116 (列島自然めぐり)

    斎藤 眞, 下司 信夫, 渡辺 真人, 北中 康文( Role: Joint author)

    文一総合出版  2012.3 

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    Responsible for pages:総ページ数:288   Language:Others  

MISC

  • Shallow magma pre-charge during repeated Plinian eruptions at Sakurajima volcano Reviewed

    Naoki Araya, Michihiko Nakamura, Atsushi Yasuda, Satoshi Okumura, Tomoki Sato, Masato Iguchi, Daisuke Miki, Nobuo Geshi

    Scientific Reports   2019.12

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    DOI: 10.1038/s41598-019-38494-x

  • Salt shell fallout during the ash eruption at the Nakadake crater, Aso volcano, Japan: evidence of an underground hydrothermal system surrounding the erupting vent

    Hiroshi Shinohara, Nobuo Geshi, Akihiko Yokoo, Takahiro Ohkura, Akihiko Terada

    Earth, Planets and Space   2018.12

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    DOI: 10.1186/s40623-018-0798-4

  • 屋久島北東部,小瀬田海岸の完新世波食ベンチ上に認められる近世のイベント礫層の起源 : 予報

    中川 正二郎, 七山 太, 佐々木 洋之, 面 将道, 下司 信夫, 渡辺 和明, 岸本 清行, 成尾 英仁, 前野 深, 奥野 充, 小林 哲夫, Nakagawa Shojiro, Nanayama Futoshi, Sasaki Hiroyuki, Omote Masamichi, Geshi Nobuo, Watanabe Kazuaki, Kisimoto Kiyoyuki, Naruo Hideto, Maeno Fukashi, Okuno Mitsuru, Kobayashi Tetsuo

    福岡大学理学集報 = Fukuoka University science reports   2017.3

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  • 口永良部島火山の過去1万年の活動 : 安山岩火山の小規模な爆発噴火とそれに伴う火砕流 (総特集 九州の火山地質学(2))

    下司 信夫, 小林 哲夫

    月刊地球   2015.5

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  • UP-15 御嶽山2014年9月噴火の火山灰粒子(緊急学術セッション(ポスター))

    宮城 磯治, 下司 信夫, 濱崎 聡志, 東宮 昭彦

    日本火山学会講演予稿集   2014.11

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  • B2-21 苦鉄質火山の火道断面構造から推測される噴火プロセス(浅部マグマ上昇過程,口頭発表)

    下司 信夫

    日本火山学会講演予稿集   2014.11

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  • C1-01 桜島火山のブルカノ式噴火による降下火山灰の粒度特性(噴火のダイナミクス,口頭発表)

    古川 竜太, 山元 孝広, 石塚 吉浩, 七山 太, 下司 信夫, 及川 輝樹, 大石 雅之

    日本火山学会講演予稿集   2014.11

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  • C1-02 桜島火山昭和火口噴火の細粒火山灰構成粒子の時系列(噴火のダイナミクス,口頭発表)

    大石 雅之, 下司 信夫

    日本火山学会講演予稿集   2014.11

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  • P2-07 西之島火山2014年噴火マグマの岩石学的特徴とマグマ脱ガス量(ポスターセッション)

    斎藤 元治, 中野 俊, 下司 信夫, 篠原 宏志, 東宮 昭彦, 宮城 磯治

    日本火山学会講演予稿集   2014.11

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    2014年6月3日に西之島火山で噴出した降下火砕物について岩石学的特徴を明らかにするとともに,マグマ脱ガス量を見積もった.降下火砕物の全岩化学組成と鉱物組み合わせは1973-74年噴火噴出物と同様であり,2014年噴火は1973-74年噴火と同様な化学的特徴を持つマグマによって引き起こされたと考えられる.メルト包有物分析と火山ガス観測による二酸化硫黄放出率から見積もられた2014年1月末のマグマ脱ガス率は地形変化から見積もられる溶岩噴出率と同程度である.

  • P2-08 西之島火山2014年噴出物の岩石学的パラメータ(ポスターセッション)

    宮城 磯治, 斎藤 元治, 下司 信夫, 中野 俊, 東宮 昭彦, 篠原 宏志

    日本火山学会講演予稿集   2014.11

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  • UP-05 御嶽山2014年9月27日水蒸気噴火の噴出量推定(緊急学術セッション(ポスター))

    宝田 晋治, 及川 輝樹, 古川 竜太, 星住 英夫, 下司 信夫, 伊藤 順一, 宮城 磯治

    日本火山学会講演予稿集   2014.11

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  • 離島活火山"諏訪之瀬島火山"の火山地質図

    嶋野 岳人, 下司 信夫, 小林 哲夫

    GSJ地質ニュース = GSJ chishitsu news   2014.7

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  • ボーリングコア試料から見た熊野酸性岩の構造と形成条件 (総特集 陸上科学掘削の将来展望(2)2013年以降に向けた提言)

    中島 隆, 下司 信夫, 及川 輝樹

    月刊地球   2014.3

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  • 火山フロントの移動とマントル構造の変化 : 関東山地火山岩のK-Ar年代からの制約

    中村 仁美, 及川 輝樹, 下司 信夫, 松本 哲一

    日本鉱物科学会年会講演要旨集   2013.9

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  • B2-12 長大なダイクシステムの研究による水平方向長距離地殻内マグマ移動プロセスの解明(マグマ供給系,口頭発表)

    石塚 治, 下司 信夫, 望月 伸竜, Taylor Rex N.

    日本火山学会講演予稿集   2013.9

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  • GSJ共同利用実験室における微小領域分析機器 : EPMAとSEM-EDS (特集 地質試料の先端分析システムとそのマネジメントの課題)

    下司 信夫, 斎藤 元治

    GSJ地質ニュース = GSJ chishitsu news   2013.3

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  • 阿蘇火山2011年5月の噴出物から推定する浅部火道プロセス (総特集 阿蘇火山の微小噴火活動)

    下司 信夫, 篠原 宏志

    月刊地球   2012.11

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  • P45 伊豆大島沿岸域の高分解能海底地形調査速報(ポスターセッション)

    石塚 治, 坂本 泉, 滝野 義幸, 八木 雅俊, 鬼頭 毅, 下司 信夫

    日本火山学会講演予稿集   2012.10

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  • A2-06 桜島火山におけるリアルタイム降灰調査の概要(桜島火山1,口頭発表)

    大石 雅之, 西来 邦章, 下司 信夫, 古川 竜太, 石塚 吉浩, 及川 輝樹, 廣田 明成, 田中 明子, 三輪 学央

    日本火山学会講演予稿集   2012.10

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  • B1-07 榛名二ツ岳,伊香保テフラ(Hr-FP)のSHCal04を適用した^<14>Cウイグルマッチング年代(火山の時空間分布,口頭発表)

    奥野 充, 八塚 槙也, 及川 輝樹, 下司 信夫, 星野 安治, 中村 俊夫

    日本火山学会講演予稿集   2012.10

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  • B3-13 諏訪之瀬島火山1813年噴火の前駆的灰噴火について(噴火プロセス,口頭発表)

    嶋野 岳人, 下司 信夫

    日本火山学会講演予稿集   2012.10

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  • 三宅島火山の連続脱ガスに伴う小噴火噴出物に含まれる玄武岩本質物から推測する火道内マグマプロセス

    下司 信夫, 篠原 宏志

    火山   2010.12

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    The Miyakejima volcano repeats small ash eruptions from the degassing vent opening inside the A.D. 2000 caldera. The juvenile glassy fragments in the tephra indicate that the basaltic magmas with primitive composition are ascending in the open conduit and degassing at the shallow depth. We examined the representative 12 tephra samples erupted between October 2001 and July 2010, and found the juvenile glassy fragments with basaltic character. Their fresh surfaces and free from alteration or weathering indicate that these glassy grains are juvenile materials. The glassy fragments occupy less than 1 vol.&#37; of the tephra, that mainly consists of the fragments of lavas and pyroclastics derived from the previous edifice. The juvenile fragments consist of volcanic glass with pale-brownish color and euhedral crystals of plagioclase, clinopyroxene and olivine up to several tens micrometers across. Larger crystals of plagioclase and olivines more than 100 micrometers are also contained as microphenocryst. The range of the Fo contents of the olivine microphenocrysts in the glassy fragments is 73-83, which is higher than that of the phenocryst olivine in the basaltic bombs erupted during the August 18, 2000 eruption and similar to that of the olivine phenocrysts derived from the primitive basaltic magma, indicating that the continuous degassing since the A.D. 2000 eruption has been driven by the basaltic magmas with primitive character. The low sulfur and chlorine contents in the groundmass glass indicate the degassing under low pressure.

  • Overview of a special issue on "geotectonic evolution of the Japanese Islands under new paradigms of the next generation (part 1-3)" (特集号 日本列島形成史と次世代パラダイム(Part 2))

    笠原 順三, 佐野 修, 下司 信夫, ISOZAKI Yukio, MARUYAMA Shigenori, YANAI Shuichi

    地學雜誌   2010.12

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    &emsp;This article provides an overview of papers collected in the special issue titled &ldquo;Geotectonic Evolution of the Japanese Islands under New Paradigms of the Next Generation (Part I-III)&rdquo; for international readers. Research on the geologic evolution of the Japanese Islands started from the geotectonic subdivision with definitions of elements and boundaries in the late 19th century. Traditionally, some remarkable faults, such as Median Tectonic Line (MTL), Fossa magna, and Tanakura Tectonic Line (TTL), were regarded as the most important; however, these apparent features were in fact formed during the Miocene opening of the Japan Sea, whereas the major structures of Japan were made by the Pacific-type orogenies throughout the Phanerozoic after the initiation of subduction at 520 Ma (the Cambrian). &emsp;Marine geophysicists have realized that the formation of accretionary complex (AC) along modern active subduction zones is rather exceptional; instead, tectonic erosion takes place dominantly. The estimated addition rate of juvenile arc crust (composed of tonalite&ndash;tronjemite&ndash;granodiorite suite; TTG) is negative at present for the entire globe, i.e., the total volume of the continental crust is currently decreasing. This indicates that tectonic erosion must also have occurred effectively in the past, and that its geological remnants need to be investigated carefully. A possible proxy geologic body for ancient tectonic erosion is a serpentinite m&eacute;lange, which often includes calc-alkaline volcanics and coeval high-P/T blueschists within serpentinite matrices as shown in the geology of Japan. The large-scale shortening of a fore-arc crust can occur solely due to tectonic erosion, which may involve more than 150 km-wide areas of missing rocks between volcanic arc and trench. The sporadic occurrence of tectonic blocks of older (520-150 Ma)TTG rocks in serpentinite m&eacute;lange indicates that four arc crusts, out of the five made by Pacific-type orogeny in Japan during the past 500 million years, have already been consumed. &emsp;The Pacific-type orogeny was revisited after recent critical discoveries of; (1) orogenic core of high-P/T regional metamorphic belt as a thin (< 2 km) solid high-T intrusion, bounded on the top and bottom by a paired fault; (2) rapid increase of 200-300 km-wide TTG belt formed by slab-melting; (3) these culminated with an approaching mid-oceanic ridge, associated with large-scale tectonic erosion; and (4) formation of an AC after ridge subduction and doming up of a sandwiched set of high-P belt and accretionary belt below and above. The Pacific-type orogeny has been ignored since the &ldquo;terrane plague&rdquo;; however, Pacific-type orogeny dominated to increase the TTG crust leading to the births of continents and supercontinent by 1.8 Ga. The extensive tectonic erosion and arc subduction through time, suggesting 10 times more TTG materials, enriched with radiogenic elements, floated at the bottom of the mantle transition zone, which generated heat to warm up the mantle up to 200 K within 100 million years in the Archean, and to 100 K in the Phanerozoic. Subducted TTG and presence of second continents in the mid-mantle may explain more general aspects of mantle dynamics, and the concept may become a frontier of solid Earth science in the 21st century. &emsp;From the viewpoint of the history of science, the previous geological studies in Japan since the Meiji Era are also summarized briefly, with special reference to the orogeny, tectonics, and geotectonic subdivision of the Japanese Islands.

    DOI: 10.5026/jgeography.119.947

  • キッチン火山実験--小麦粉溶岩で火山を作ろう! (特集 地質情報展2009おかやま)

    西来 邦章, 下司 信夫, 宝田 晋治

    地質ニュース   2010.8

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  • 霧島火山新燃岳2008年8月22日噴火の噴出物

    下司 信夫, 宝田 晋治, 筒井 正明, 森 健彦, 小林 哲夫

    火山   2010.2

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    A phreatic eruption occurred on August 22, 2008 from Shinmoedake Volcano, one of the members of Kirishima volcanic group, Kyushu, southwestern Japan. Some explosive craters and eruption fissures aligning in E-W direction for 800 meters were formed inside the summit crater and the western flank of Shinmoedake Volcano. These craters produced clay-rich tephra, consisting of non-juvenile lithic fragments with various degree of hydrothermal alteration. Ballistic blocks distribute in an area within 800 meters from the main crater. The total volume of the tephra produced this eruption is evaluated as 2×10^8kg. Distribution of the tephra indicates that the main source of the tephra is S-17 crater, which is the largest crater located at the center of the crater chain. More than 70&#37; of the tephra deposit inside the area within 1km from the craters, suggesting the low height of the eruption cloud. Absence of the juvenile materials suggests that this eruption was phreatic caused by a rapid release of steam from the hydrothermal system beneath Shinmoedake Volcano.

  • 三重県熊野市の井内浦観測点掘削で得られたボーリングコア試料からみた熊野酸性岩の構造と岩石学的特徴 (特集 東南海・南海地震予測のための地下水等総合観測点整備に関連する調査研究報告会)

    下司 信夫, 中島 隆, 及川 輝樹

    地質ニュース   2009.10

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  • 沖縄島東方沖の海底堆積物

    板木拓也, 片山肇, 池原研, 兼子尚知, 川村紀子, 下司信夫

    沖縄本島東方の海洋地質学的研究,産業技術総合研究所地質調査総合センター速報   2009.3

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  • S-27 地質情報の活用による商品開発 : 化石チョコレート,世界遺産屋久島ポスター及び屋久島地質図Tシャツの例((4)地域振興と地質学-ジオパークが開く地域と地質学の未来-,口頭発表,シンポジウム)

    斎藤 眞, 利光 誠一, 小笠原 正継, 森尻 理恵, 下司 信夫, 青木 正博, 井川 敏恵, 長森 英明, 古谷 美智明, 大熊 洋子, 中島 和敏, 川畑 晶

    日本地質学会学術大会講演要旨   2008.9

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  • P-187 世界遺産屋久島の地質ポスター,地質図を用いた新たなアウトリーチの例(29.地学教育・地学史,ポスター発表,一般講演)

    斎藤 眞, 小笠原 正継, 下司 信夫, 長森 英明

    日本地質学会学術大会講演要旨   2008.9

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  • 特集号「地殻からマントルまで-モホ(面)とは何か?-」はじめに

    笠原 順三, 阿部 なつ江, 荒井 章司, 下司 信夫, 熊谷 英憲, 丸山 茂徳, 小原 一成, 小原 泰彦

    地學雜誌   2008.2

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    DOI: 10.5026/jgeography.117.1

  • 東太平洋海膨のオフリッジ火山まモホ遷移帯起源か?

    海野 進, 下司 信夫, 熊谷 英憲, 岸本 清行

    地學雜誌   2008.2

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    &amp;emsp;A large number of intraplate volcanoes erupted two to several hundred kilometers off the fast-spreading East Pacific Rise (EPR). These volcanoes consist of large lava fields, monogenetic volcanoes, and linear chains of monogenetic volcanoes and volcanic ridges. Large lava fields of 7-26 km3 in volume are known at 8&amp;deg;N, 14&amp;deg;S, and 16&amp;deg;S within 2-19 km from the rise axis and from the top 75-100 m of ODP Site 1256 on the 15 Ma Cocos plate. Monogenetic volcanoes form within &amp;sim;20 km from the rise axis or on the basement < 200 kyr, and are evenly distributed over the rise axis. Linearly aligned volcanoes and volcanic ridges occur farther from the rise axis than large lava fields and monogenetic volcanoes, and run subparallel to the direction of the Pacific plate motion. The Sojourn Ridge, the largest volcanic ridge, extends up to 440 km in length and is several hundred cubic kilometers in volume. Eruptive ages along a volcanic ridge and a volcano chain contradict the hot-spot origin of these volcanic features. Negative free-air and residual mantle Bouguer anomalies correlate well with the linearly aligned volcanoes and volcanic ridges, suggesting excess magma supply beneath the volcanic edifices. Seismic experiments show volcanic ridges have no keel below the Moho, indicating compensation of surface loading by plate flexure and underplating. &amp;emsp;Whole rock compositions of off-ridge volcanoes have a much wider spectrum than the adjacent axial lavas, spanning from depleted NMORB through TMORB to isotopically fertile EMORB. Some off-ridge lavas could be produced by the fractional crystallization of the same parent magma as the adjacent axial lavas. However, most off-ridge lavas originate from different parent magmas than the neighboring axial lavas. Some TMORB magmas including the 14&amp;deg;S large lava field are the mixing product of the NMORB and EMORB magmas. Copious differentiated lavas of the large lava fields require a large magma chamber as a the site for crystallization differentiation and magma mixing. The lava geochemistry of off-ridge volcanoes strongly suggests the presence of a magma source that is independent of the axial magma plumbing system. &amp;emsp;Seismic tomography and seafloor compliance measurements beneath the northern EPR indicate that the presence of melt across the rise axis is restricted in a narrow zone &amp;sim;4 km in width through the crust, but has a 10-14 km wide distribution in the uppermost mantle. Broad distribution, volume, and geochemistry of off-ridge monogenetic volcanoes and large lava fields strongly suggest that the off-ridge volcanoes originated from the Moho transition zone (MTZ). The MTZ is formed by a reaction between the uprising magma and the host mantle peridotite, leaving replacive dunite that experienced variable depletion and enrichment processes. Passive asthenospheric upwelling beneath the fast-spreading ridges produces a broad partial melt zone, through which magma ascends and accumulates beneath the off-ridge lithosphere. More depleted off-ridge magmas than axial magmas differentiate and mix with residual magmas in the MTZ, and react with variably enriched, impregnated dunite, resulting in variety of off-ridge lava compositions. &amp;emsp;Small clusters of volcanoes and linear volcano chains are created by partial melting in asthenospheric return flows or local instability of the thermal boundary layer beneath the cooling lithosphere. Linear volcano chains will develop into long and robust volcanic ridges extending several hundred kilometers in length.

    DOI: 10.5026/jgeography.117.190

  • O-21 熊野酸性岩ボーリングコアの凝灰岩岩相と定置様式(新しいカルデラ像を探る,口頭発表,一般講演)

    及川 輝樹, 三浦 大助, 下司 信夫, 新正 裕尚, 角井 朝昭, 中島 隆, 小泉 尚嗣

    日本地質学会学術大会講演要旨   2007.9

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  • 琉球弧の火山活動 (特集:沖縄海域(その2))

    下司 信夫, 石塚 治

    地質ニュース   2007.6

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  • P69 巡回展「三宅島火山~その魅力と噴火の教訓~」(ポスターセッション,日本火山学会2006年秋季大会)

    伊藤 和明, 三松 三朗, 佐藤 公, 池辺 伸一郎, 菊川 茂, 吉田 大祐, 下司 信夫, 川畑 晶, 中島 和敏, 青木 正博, 谷田部 信郎, 宮下 加奈

    日本火山学会講演予稿集   2006.10

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  • 鹿児島県口永良部島火山最近約3万年間の噴火活動

    下司 信夫, 小林 哲夫

    火山   2006.2

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    Volcanic history of Kuchinoerabujima Volcano in the last 30,000 years is reconstructed based on tephra stratigraphy. Kuchinoerabujima is a volcanic island which is a cluster of at least nine volcanic edifices; Gokyo, Jyogahana, Ban-yagamine, Takadomori, Noike, Kashimine, Hachikubo, Furutake and Shintake. Eruptions within the last 30,000 years occurred from Noike, Hachikubo, Furutake and Shintake volcanoes. Two major pumice and scoria eruptions occurred between 15 and 11 ka after an inactive period since ca. 30ka. NoikeYumugi tephra (15-14ka, DRE>0.06km^3), erupted from the summit of Noike Volcano, consists of Yumugi pumice fall deposit and Nemachi pyroclastic flow deposit. Furutake-Megasaki tephra (12-11 ka, DRE ca. 0.8km^3) erupted from Furutake Volcano and consists of Furutake agglutinate, Furutake scoria flow deposit and Megasaki scoria fall deposits. Volcanic edifice of Older Furutake was built during the 12-11 ka eruption. Eruption style changed around 10ka, after the collapse of Older Furutake Volcano. Activities of Yougner Furutake and Shintake Volcanoes are characterized with effusion of lava flow and no major pumice eruption is recognized. Lithic tephra erupted from Younger Furutake and Shitake Volcanoes within the last 10,000 indicates repetitive Vulcanian-type and phreatomagmatic eruptions. All historical eruptions since 1841 occurred at and around Shintake crater and were Vulcanian-type explosions with emission of magmatic materials and phreatic explosions.

  • 口永良部島火山の火山地形と地質

    下司 信夫, 小林 哲夫

    火山   2006.2

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  • 三宅島火山2000年噴火のマグマ供給系

    下司 信夫, 嶋野 岳人, 長井 雅史, 中田 節也

    火山   2002.11

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    Language:Japanese  

    Erupted magma of the 2000 eruption of the Miyakejima volcano changed from basaltic andesite to basalt during the caldera formation, from aphyric basaltic andesite with SiO_2=54 wt.&#37; to plagioclase-phyric basalt with SiO_2=51.5 wt.&#37;. Whole-rock compositions of the basaltic andesite of the June and July eruptions are plotted on the extension of the temporal variation of the previous eruptive materials, suggesting that the andesitic magma erupted in June and July eruptions were driven from the magma system worked for the last 500 years. Petrological character of the basalt in the eruptive materials of August, by contrast, is different from the previous lavas of the Miyakejima volcano. This shows that a new basaltic magma ascended to the shallow magma system after the caldera collapse. Identical ratio of the incompatible elements among the eruptive materials of the 2000 eruption and the recent eruptions suggests that they were driven from a common parental magma.

  • RADARSAT 画像による三宅島2000年陥没カルデラの地形解析

    金子 隆之, 須藤 昇, Wooster Martin J., 下司 信夫, 嶋野 岳人, 長井 雅史, 中田 節也

    火山   2001.8

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    Language:English  

    噴火中の火山で, どのような地形変化が起きているかを知ることは, 活動状況を把握するうえで, 最も重要な点の一つである. しかし, 我が国のような湿潤な気候帯では, しばしば, 山頂部が雲に覆われ観測できない事態が起きる. このような場合, 合成開ロレーダー(SAR)は, 昼夜, 天候, 噴煙等に左右されないため, 火山の地形変化の監視に有効であると考えられる. しかし, SAR 画像は, 独自の歪みをもっため,地形図との対応関係を知るのが容易でないなどの問題がある.本論は,RADARSATSAR 画像をGround Control Points (GCP) を用いたマッチングにより地形図上に重ね合わせ, 2000年7月に噴火を開始した三宅島陥没カルデラ縁の拡大状況の推定を行った. この際フォアショートニングによる歪みを抑えるため, カルデラ縁に近い場所にGCPを設定した. 得られた結果を空中写真等からの推定と比較すると,両者のずれは大きい部分でも1OOm程度であり, 比較的良く一致していることがわかった. このことから, RADARSATSAR 画像は, 緊急時にカルデラ縁の位置を推定するといった用途には十分利用できると考えられる.

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Professional Memberships

  • 日本火山学会

  • 日本地質学会

  • International Association of Volcanology and Chemistry of the Earth's Interior

Committee Memberships

  • commissioner   Foreign country

    2023.7 - 2027.6   

  • Executive   Domestic

    2022.7 - 2024.6   

  • 日本火山学会   編集委員長   Domestic

    2022.7 - 2024.6   

Academic Activities

  • 火山

    2022.7 - Present

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    Type:Academic society, research group, etc. 

Research Projects

  • 岩相の特徴量自動認識による火山性露頭その場調査手法の研究

    Grant number:22H01326  2022 - 2024

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    Grant type:Scientific research funding

  • マグマ過剰圧とその時間変化の追跡による爆発的割れ目噴火推移過程の解明

    Grant number:22K03785  2022 - 2024

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    Grant type:Scientific research funding

  • 火道構造から推測する噴火駆動力と爆発的噴火挙動との関係

    Grant number:19K04024  2019 - 2022

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    Grant type:Scientific research funding

  • 浅部マグマ過程のその場観察実験に基づく準リアルタイム火山学の構築

    Grant number:16H06348  2016 - 2020

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    Grant type:Scientific research funding

  • 高温変形実験による浅所貫入マグマ物性の研究

    Grant number:16H02237  2016

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    Grant type:Scientific research funding

  • 2015年口永良部島噴火に関する総合調査

    Grant number:15H05794  2015

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    Grant type:Scientific research funding

  • 火山噴火の物質収支

    Grant number:25287115  2013 - 2015

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    Grant type:Scientific research funding

  • 爆発的噴火をもたらす浅部火道システムの構造発達過程

    Grant number:24510251  2012 - 2014

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    Grant type:Scientific research funding

  • オフリッジ火山から高速拡大海嶺のモホ遷移帯マグマプロセスを探る

    Grant number:22403004  2010 - 2013

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    Grant type:Scientific research funding

  • 不均質な地質構造をもつ岩盤中でのダイク発達メカニズムの解明

    Grant number:21710182  2009 - 2011

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    Grant type:Scientific research funding

  • FEP解析を応用した火山噴火の想定シナリオ作成手法の高度化

    Grant number:20310107  2008 - 2010

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    Grant type:Scientific research funding

  • 岩脈群の構造・化学組成分布からみた火山マグマ供給系の発達過程

    Grant number:98J04993  1998 - 2000

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    Grant type:Scientific research funding

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Travel Abroad

  • 2012.9 - 2014.3

    Staying countory name 1:Italy   Staying institution name 1:ローマ第三大学