Masashi Nagai - My portal

Profile Information

Affiliation: Research Fellow, Volcano Disaster Resilience Research Division, National Research Institute for Earth Science and Disaster Resilience
: Part-time Lecturer, Department of Earth & Environmental Sciences, College of Humanities and Sciences, Nihon University

Degree: Ph.D.(Mar, 2015, Kagoshima University)

Researcher number: 10571317
J-GLOBAL ID: 202101011252653860
researchmap Member ID: R000016793

Research Areas

Natural sciences / Solid earth science / volcanic geology

Research History

Research Fellow, Volcano Disaster Resilience Research Division, National Research Institute for Earth Science and Disaster Resilience

Papers

Post-eruption field survey of ash-fall deposits using the JVDN system: Case study of the October 20, 2021 eruption of Nakadake first crater, Aso Volcano, Japan

Miyabuchi, Y, Nagai, M, Nakada, S, Ozawa, T, Furukawa, R, Ishizuka, O, Minami, Y, Conway, C, Itoh, J

Bulletin of the Volcanological Society of Japan, 69(2) 61-70, Jun, 2024 Peer-reviewed
Classification of Volcanic Ash Particles with a Convolutional Neural Network on RGB Microphotographs: Towards Real-Time Monitoring of an Ongoing Eruption

Takahiro MIWA, Masashi NAGAI, Hideki UEDA, Akihiko YOKOO

Report of the National Research Institute for Earth Science and Disaster Resilience, (88) 1-7, Dec, 2023
Geological findings in the 2021 Nishinoshima comprehensive scientific research project

Masashi NAGAI, Fukashi MAENO, Takayuki KANEKO

OGASAWARA RESEARCH, 49 45-69, Mar, 2023 Lead author
Impact on the Electric Infrastructure Due to Volcanic Ash from a Hydrovolcanic Eruption of Aso Volcano in 2016

Masashi Nagai, Setsuya Nakada

Journal of Disaster Research, 17(5) 829-838, Aug 1, 2022 Peer-reviewedLead author
Total mass estimate of the January 23, 2018, phreatic eruption of Kusatsu-Shirane Volcano, central Japan

Nobuko Kametani, Yasuo Ishizaki, Mitsuhiro Yoshimoto, Fukashi Maeno, Akihiko Terada, Ryuta Furukawa, Ryo Honda, Yoshihiro Ishizuka, Jiro Komori, Masashi Nagai …

Earth, Planets and Space, 73(1), Dec, 2021 Peer-reviewed
High-resolution Reconstruction of the History of Large-scale Eruptions of Asama-Maekake Volcano based on the Stratigraphy of Pyroclastic Fall Deposits

Maya YASUI, Masaki TAKAHASHI, Tatsuo KANAMARU, Masashi NAGAI

BULLETIN OF THE VOLCANOLOGICAL SOCIETY OF JAPAN, 66(4) 293-325, Dec, 2021 Peer-reviewed
Stratigraphy and Lithologic Features of Borehole Core from Sobetsu Observation Well, Usu Volcano, Hokkaido, Japan

Masashi NAGAI, Hiromitsu OSHIMA, Mitsuhiro NAKAGAWA, Mitsuhiro YOSHIMOTO, Akiko MATSUMOTO, Eiji YAMAMOTO, Toshikazu TANADA, Toru DANHARA, Hideki IWANO

Technical Note of the National Research Institute for Earth Science and Disaster Resilience, (456) 1-36, Feb, 2021 Lead author
Sedimentation process of ashfall during a Vulcanian eruption as revealed by high-temporal-resolution grain size analysis and high-speed camera imaging

T. Miwa, Y. Iriyama, M. Nagai, F. Nanayama

Progress in Earth and Planetary Science, 7(1), Dec, 2020 Peer-reviewed
Recognition and stratigraphic correlation of marine Pleistocene deposits beneath the Hidaka Upland based on diatom assemblages in the Hidaka Observation Well, Saitama Prefecture, Japan

Tomonori NAYA, Masashi NAGAI, Kentaro OMURA

BULLETIN OF THE GEOLOGICAL SURVEY OF JAPAN, 71(5) 463-472, Nov 30, 2020
Correlation between a Tephra Bed from Deep (2038 m) Underground below Chiba City, and Kd48 in the Lowermost Kiwada Formation (Lower Pleistocene) on the Boso Peninsula

Masayuki UTSUNOMIYA, Kiyohide MIZUNO, Tomonori NAYA, Kentaro OMURA, Masashi NAGAI

Journal of Geography (Chigaku Zasshi), 129(3) 355-374, Jun 25, 2020 Peer-reviewed
Shallow magmatic hydrothermal eruption in april 2018 on ebinokogen ioyama volcano in kirishima volcano group, Kyushu, Japan

Yasuhisa Tajima, Setsuya Nakada, Fukashi Maeno, Toshio Huruzono, Masaaki Takahashi, Akihiko Inamura, Takeshi Matsushima, Masashi Nagai, Jun Funasaki

Geosciences (Switzerland), 10(5), May, 2020 Peer-reviewed
Development of a Data Sharing System for Japan Volcanological Data Network

Hideki Ueda, Taishi Yamada, Takahiro Miwa, Masashi Nagai, Takanori Matsuzawa

Journal of Disaster Research, 14(4) 571-579, Jun 1, 2019 Peer-reviewed
Petrology of Oshi Pyroclastic Flow Deposits, Kusatsu-Shirane volcano

N. Katsuoka,, Y. Ishizaki,, M. Nagai,, A. Terada,

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN, 2019 143-143, 2019
Conduit processes during the climactic phase of the Shinmoe-dake 2011 eruption (Japan): Insights into intermittent explosive activity and transition in eruption style of andesitic magma

Yuki Suzuki, Fukashi Maeno, Masashi Nagai, Hitomi Shibutani, Syouhei Shimizu, Setsuya Nakada

Journal of Volcanology and Geothermal Research, 358 87-104, Jun 1, 2018 Peer-reviewed
Phreatic eruptions and deformation of Ioto Island (Iwo-jima), Japan, triggered by deep magma injection

Hideki Ueda, Masashi Nagai, Toshikazu Tanada

EARTH PLANETS AND SPACE, 70, Mar, 2018
Proximal eruptives of the 23 Jan, 2018 eruption of Kusatsu-Shirane volcano

Ishizaki Y., Kametani N., Terada A., Yoshimoto M., Honda R., Ishimine Y., Nagai M., Furukawa R., Sekiguchi Y., Yanada T. …

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN, 2018 75-75, 2018
Distribution of ballistic ejecta of the phreatic eruption at Kusatsu-Shirane volcano, on 23 Jan, 2018

Yoshimoto M., Honda R., Nagai M., Furukawa R., Sekiguchi Y., Yanada T., Terada A., Ishimine Y., Ishizaki Y., Kametani N. …

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN, 2018 76-76, 2018
NIED’s V-net, the fundamental volcano observation network in Japan

Toshikazu Tanada, Hideki Ueda, Masashi Nagai, Motoo Ukawa

Journal of Disaster Research, 12(5) 926-931, Oct, 2017 Peer-reviewed
Stratigraphy and Lithologic Features of Volcanic Rocks from the Drill Hole of the Nikenya and Yazawahara Observation Stations of Kusatsu-Shiranesan Volcano, Central Japan

NAGAI Masashi, UEKI Kenta, TERADA Akihiko, HOKANISHI Natsumi, INUI Mutsuko, NOGAMI Kenji

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN, 2017 205-205, 2017
Reconstruction of a phreatic eruption on 27 September 2014 at Ontake volcano, central Japan, based on proximal pyroclastic density current and fallout deposits the Phreatic Eruption of Mt. Ontake Volcano in 2014 5. Volcanology

Fukashi Maeno, Setsuya Nakada, Teruki Oikawa, Mitsuhiro Yoshimoto, Jiro Komori, Yoshihiro Ishizuka, Yoshihiro Takeshita, Taketo Shimano, Takayuki Kaneko, Masashi Nagai

Earth, Planets and Space, 68(1), Dec 1, 2016 Peer-reviewed

Misc.

The eruption sequence and products of the 2022 eruption off the Okinahama beach, Ioto (Iwojima), Japan

長井雅史, 中田節也, 上田英樹, 小園誠史, 三輪学央, 安田敦, 前野深, 外西奈津美, 佐野貴司, 谷健一郎 …

日本火山学会講演予稿集, 2022, 2022
Assessment of volcanic hazards following the July 2022 magma eruption at Ioto volcano, Ogasawara

中田節也, 長井雅史, 藤田英輔

日本火山学会講演予稿集, 2022, 2022
Geothermal activities around Ioyama since 2014 and the associated disaster incident for the Kirishima volcano in Kyushu, Japan

田島靖久, 中田節也, 長井雅史, 前野深, 松島健

日本地球惑星科学連合大会予稿集(Web), 2022, 2022
Small Eruption at the Ebinokogen Ioyama Volcano of the Kirishima Volcano Group in April 2018

田島靖久, 中田節也, 長井雅史, 前野深, 渡邉篤志

火山, 64(2) 147‐151(J‐STAGE), 2019
Amounts of tephra fall deposit from Shinmoedake (Kirishima volcanoes) 2018 eruption (Report 1)

Oikawa T., Kawanabe Y., Ito J., Maeno F., Hasenaka T., Kawaguchi M., Nagai M., Nakada S., Tajima Y., Miyabuchi Y. …

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN, 2018 231-231, 2018
Comparison of the observation of grain size of falling ash by SPC with PARSIVEL2 in the laboratory test

Kubo Tomohiro, Miyagi Yousuke, Miwa Takahiro, Iriyama Yu, Nagai Masashi

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN, 2018 187-187, 2018
P15 Stratigraphy and Radiometric Ages of Volcanic Rocks from the Drill Hole of the Hoshimata Observation Station of Kusatsu-Shiranesan Volcano, Central Japan

NAGAI Masashi, UEKI Kenta, MIZUNO Yuhki, TANAKA Yuhki, INUI Mutsuko, NOGAMI Kenji, TANADA Toshikazu

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN, 2015 113-113, 2015
P75 Detailed observation of summit caldera in Miyakejima volcano by using small fixed wing UAV

Miwa Takahiro, Inoue Hiroshi, Nagai Masashi, Miyagi Yousuke, Tanada Toshikazu

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN, 2015 173-173, 2015
P1-32 Shallower resistivity structure around the volcanic observation hole of Kuchinoerabujima

Tanada T., Nagai M., Kawabata H., Ueda H., Ishikawa H., Harada M., Okada C., Ishikawa T.

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN, 2014 150-150, 2014
P2-35 Eruptive activity of Kuchinoerabujima in 2014

UEDA Hideki, NAGAI Masashi, MIWA Takahiro, KAWABATA Hirofumi, TANADA Toshikazu, MAESAKA Takeshi, IWANAMI Koyuru

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN, 2014 187-187, 2014
P26 Evolution of conduit flow during the 2011 eruption of Shinmoe-dake, Japan : insights into cyclic sub-Plinian activity and shifting eruption style of andesite magma

Suzuki Y., Maeno F., Nagai M., Nakada S., Ichihara M.

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN, 2013 126-126, 2013 Peer-reviewed
Inventory of Important Geological Sites in the Somma of Hakone Volcano Which Should Be Preserved for the Planning of the Odawara-Hakone Geopark

(47) 287-339, 2012
Distribution and characteristics of tephra on the February 2, 2009 eruption of Asama volcano, Central Japan

Proceedings of the Institute of Natural Sciences Nihon University Department of geosystem sciences, (45) 265-288, 2010
New view for geologic evolution of the Hakone volcano: unique active volcano erupted on the arc-arc collisional tectonic boundary, cut across by active strike-slip fault

Chikyu monthly, 31(2) 71-76, Feb, 2009
15万年前以降における箱根火山の浅部マグマ供給システムとテクトニクス場--横ずれ活断層システムに切られた活火山 (総特集伊豆の衝突と神奈川県西部のテクトニクス) -- (テクトニックモデル)

高橋正樹, 長井雅史

号外地球, (57) 173-181, 2007
Whole-rock major element chemistry for eruptive products of Somma of Hakone Volcano, Central Japan

Proceedings of the Institute of Natural Sciences Nihon University Department of geosystem sciences, (42) 71-95, 2007
Mass Estimation and Characteristics of Ejecta from the 2004 Eruption of Asama Volcano(＜Special Section＞The 2004 Eruption of Asama Volcano(2))

YOSHIMOTO Mitsuhiro, KANEKO Takayuki, HOSHIZUMI Hideo, ISHIZUKA Yoshihiro, FURUKAWA Ryuta, NOGAMI Kenji, ONIZAWA Shinya, NIIHORI Kenji, SUGIMOTO Takeshi, NAGAI Masashi …

BULLETIN OF THE VOLCANOLOGICAL SOCIETY OF JAPAN, 50(6) 519-533, 2005
箱根火山岩類のSr・Nd同位体組成

永井匡, 高橋正樹, 長井雅史

日本大学文理学部自然科学研究所研究紀要地球システム科学, (40) 101-106, 2005
O-44 Across-arc variation of magmatic chemistry in the Hakone and Fuji volcanic region in the northern tip of Izu-Ogasawara arc.

TAKAHASHI Masaki, NAGAI Tadashi, NAGAI Masashi, NISHI Naoto, NAITO Shohei, HIRAHARA Yuka, SHUTO Kenji

Annual Meeting of the Geological Society of Japan, 111th 47-47, 2004
Pictorial 1 : Chronology of the Miyakejima 2000 Eruption

Setsuya NAKADA, Masashi NAGAI, Atsushi YASUDA, Taketo SHIMANO, Nobuo GESHI, Marekazu OHNO, Takako AKIMASA, Takayuki KANEKO, Toshitsugu FUJII

Journal of Geography (Chigaku Zasshi), 110(2) Plate3-Plate5, 2001

Books and Other Publications

箱根ジオミュージアム展示解説書

長井雅史 (Role: Contributor, １－３箱根火山の形成史)

箱根町企画観光部観光課箱根ジオミュージアム, Mar, 2024

Presentations

Data integration, forecasting and resilience by a way to view changes in volcanic activity as state transitions

Hideki UEDA, Takanori MATSUZAWA, Takahiro MIWA, Masashi NAGAI

The Volcanologicai Society of Japan 2023 Fall Meeting, Oct 20, 2023
Characteristics of the seafloor deposits of the Fukutoku-Oka-no-Ba 2021 eruption revealed from rapid response research cruises

K. Tani, T. Sano, O. Ishizuka, T. Oikawa, H. Katayama, Y. Suzuki, H. Minami, M. Nagai, T. Shimano, M. Nakamura, T. Ukita, F. Maeno, T. Mizuno, I. McIntosh

The Volcanologicai Society of Japan 2023 Fall Meeting, Oct 20, 2023
Ash fall survey after the October 20, 2021 eruption of Nakadake first crater, Aso Volcano using the JVDN system

MIYABUCHI, Y, NAGAI, M, NAKADA, S, OZAWA, T, FURUKAWA, R, ISHIZUKA, O, MINAMI, Y, CONWAY, C, ITOH, J

The Volcanologicai Society of Japan 2023 Fall Meeting, Oct 19, 2023
Shape parameter measurements of standard tephra samples via DIA in each particle

Kosei TAKISHITA, Takahiro MIWA, Masashi NAGAI, Setsuya NAKADA, Takehiko SUZUKI

The Volcanologicai Society of Japan 2023 Fall Meeting, Oct 18, 2023
Changes of the amounts and sulfur isotope compositions of sulfur minerals in volcanic ash

Aoi Hirata, Tsukasa Ohba, Takumi Imura, Ryohei Takahashi, Pearlyn Cabarubias Manalo, Masashi Nagai, Hinako Sato, Masamichi Ikeda

The Volcanologicai Society of Japan 2023 Fall Meeting, Oct 18, 2023
P-T condition of magma from the 2022 eruption at Ioto volcano, Ogasawara, Japan

Miwa T, Nagai M, Ueda H, Kozono T, Nakada S, Yasuda A

The Volcanologicai Society of Japan 2023 Fall Meeting, Oct 18, 2023
Radiometric Dating for the Early Volcanic Edifices of Hakone Volcano, Central Japan

Masashi NAGAI, Masaki TAKAHASHI

The Volcanologicai Society of Japan 2023 Fall Meeting, Oct 18, 2023
Eruption activities from 2012 to 2022 on Ioto (Iwojima) Volcano, Izu-Bonin arc

Masashi NAGAI, Takahiro Miwa, Hideki Ueda, Setsuya Nakada, Tetsuo Kobayashi, Taku Ozawa, Toshikazu Tanada, Takashi Hirose, Tomofumi Kozono

Japan Geoscience Union Meeting 2023, May 24, 2023
Water content in phreatic jet at Ioto volcano: Integration of geological and geophysical approaches

Takahiro Miwa, Aika K Kurokawa, Masashi NAGAI, Tomofumi Kozono, Hideki Ueda, Toshikazu Tanada

Japan Geoscience Union Meeting 2023, May 24, 2023
Proposal of the procedure of creating the time – accumulated eruption volume step diagram

Mitsuhiro Nakagawa, Yasuo Miyabuchi, Takeshi Hasegawa, Ryuta FURUKAWA, Shimpei Uesawa, Masashi NAGAI

Japan Geoscience Union Meeting 2023, May 23, 2023
Detailed seafloor morphology and bubble plumes around Ioto in the Izu-Bonin Arc

Masashi NAGAI, Hiroki Minami, Noritsune Seo, Kenichiro Tani

Japan Geoscience Union Meeting 2023, May 23, 2023
Development of the JVDN system (volcano observation data sharing system)

Hideki Ueda, Takashi Hirose, Takanori Matsuzawa, Takahiro Miwa, Masashi NAGAI, Yuhki Kohno

Japan Geoscience Union Meeting 2023, May 23, 2023
The origin of magmatic volatiles and the current state of the hydrothermal system of Ioto volcano inferred from helium and carbon isotope ratios of fumaroles and hot spring gases

Hirochika Sumino, Masashi NAGAI, Takashi Hirose, Takahiro Miwa, Muga Yaguchi

Japan Geoscience Union Meeting 2023, May 23, 2023
Assessment of volcanic hazards following the July 2022 magma eruption at Ioto volcano, Ogasawara

Setsuya Nakada, Masashi Nagai, Eisuke Fujita

THE VOLCANOLOGICAL SOCIETY OF JAPAN 2022 FALL MEETING, Oct 17, 2022
Monitoring method of volcanic tremors caused by eruptions using data from a wide-area seismic network

Hideki UEDA, Takashi HIROSE, Takanori MATSUZAWA, Takahiro MIWA, Masashi NAGAI, Yuhki KOHNO

THE VOLCANOLOGICAL SOCIETY OF JAPAN 2022 FALL MEETING, Oct 14, 2022
Characteristics of eruptive activity at Ioto during July and August 2022 inferred from seismic records

Takashi Hirose, Hideki Ueda, Tomofumi Kozono, Masashi Nagai

THE VOLCANOLOGICAL SOCIETY OF JAPAN 2022 FALL MEETING, Oct 13, 2022
The eruption sequence and products of the 2022 eruption off the Okinahama beach, Ioto(Iwojima), Japan

Masashi Nagai, Setsuya Nakada, Hideki Ueda, Tomofumi Kozono, Takahiro Miwa, Atsushi Yasuda, Fukashi Maeno, Natsumi Hokanishi, Takashi Sano, Kenichiro Tani, Teruki Oikawa, Tetsuo Kobayashi

THE VOLCANOLOGICAL SOCIETY OF JAPAN 2022 FALL MEETING, Oct 13, 2022
An attempt to obtain findings on volcanic history from distal turbidite deposits: the example of Ogasawara Ioto (Iwojima) Volcano

Masashi NAGAI, Takahiro Miwa, Tetsuo Kobayashi

Annual Meeting of the Geological Society of Japan, Sep 4, 2022
Rapid response seafloor surveys of the Fukutoku-Oka-no-Ba Volcano, Izu-Bonin Arc: Unraveling the eruption dynamics of the August 2021 eruption

Kenichiro Tani, Osamu Ishizuka, Hiroki Minami, Teruki Oikawa, Hajime Katayama, Yoshiaki Suzuki, Taketo Shimano, Masashi NAGAI, Fukashi Maeno, Michihiko Nakamura, Naoto Jimi, Takashi Sano

Japan Geoscience Union Meeting 2022, Jun 1, 2022
Geothermal activities around Ioyama since 2014 and the associated disaster incident for the Kirishima volcano in Kyushu, Japan

Yasuhisa Tajima, Setsuya Nakada, Masashi Nagai, Fukashi Maeno, Takeshi Matsushima

Japan Geoscience Union Meeting 2022, May 27, 2022

Teaching Experience

Research Projects

Integrated study on the 2015 eruption at the Kuchinoerabujima volcano

Grants-in-Aid for Scientific Research, Grant-in-Aid for Special Purposes, Japan Society for the Promotion of Science, Jun, 2015 - Mar, 2016

Iguchi Masato, KANDA Wataru, MORI Toshiya, GESHI Nobuo, TANAKA Hiroshi, SEKIYA Naoya, KURI Miwa, SAKAMOTO Mayumi, HASHIMOTO Manabu, NAKAO Shigeru, Ohminato Takao, MAKI Norio, ICHIKO Taro, YAMADA Takashi, JITOZONO Takashi, TANADA Toshikazu, TAMEGURI Takeshi, NAKAMICHI Haruhisa, SUZUKI Yujoro, TAKARADA Shinji, MIKI Daisuke, NAKADA Setsuya, KOBAYASHI Tetsuo, YAMAMOTO Keigo, SHINOHARA Hiroshi, NOGAMI Kenji, OZAWA Taku, MIWA Takahiro, NAGAI Masashi, KOYAMA Takao, OHKURA Takahiro
Reconstruction of the burial process of the archaeological site buried by volcanic eruptions and the analysis of the eruption sequence

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research on Priority Areas, Japan Society for the Promotion of Science, 2004 - 2009

FUJII Toshitsugu