ハセガワ タケシ
長谷川 健教授
Takeshi HASEGAWA

■研究者基本情報

組織

  • 理学部 理学科 地球環境科学コース
  • 理工学研究科(博士前期課程) 理学専攻
  • 理工学研究科(博士後期課程) 複雑系システム科学専攻
  • 基礎自然科学野 地球環境科学領域

研究分野

  • 自然科学一般, 固体地球科学

研究キーワード

  • カルデラ
  • 噴火
  • 火成岩岩石学
  • 火山地質学
  • 火山学
  • マグマ
  • 第四紀
  • 自然災害
  • 岩石学
  • 火山

学位

  • 2007年06月 博士(理学)(北海道大学)
  • 2004年03月 修士(理学)(北海道大学)

学歴

  • 2004年04月 - 2007年06月, 北海道大学, 大学院理学研究科, 地球惑星科学専攻博士後期課程

経歴

  • 2024年10月 - 現在, 茨城大学, 理学部理学科(地球環境科学コース), 教授
  • 2014年04月 - 2024年09月, 茨城大学 理学部理学科(地球環境科学コース), 准教授
  • 2009年11月 - 2013年03月, 茨城大学, 理学部理学科(地球環境科学コース), 助教
  • 2007年07月 - 2009年10月, 北海道大学, 大学院理学研究院, 博士研究員

委員歴

  • 2025年04月 - 現在, 運営委員会 議長, Earth, Planets and Space
  • 2024年01月 - 現在, 編集委員, Earth, Planets and Space
  • 2022年05月 - 現在, 原子炉安全専門審査会・核燃料安全専門審査会 臨時委員, 原子力規制委員会
  • 2020年02月 - 現在, 大会セッションコンビーナ(代表), 日本地球惑星科学連合
  • 2019年 - 現在, 他学会関連担当委員, 日本火山学会
  • 2018年04月 - 現在, 総合調査調査員, 茨城県自然博物館
  • 2018年04月 - 現在, 火山研究人材育成コンソーシアム構築事業 次世代火山研究者育成プログラム 担当責任者, 文部科学省
  • 2017年04月 - 現在, 第4次尾瀬総合学術調査団調査員, 公益財団法人 尾瀬保護財団
  • 2012年 - 現在, 客員研究員, 産業技術総合研究所
  • 2019年04月 - 2025年03月, 運営委員会 会計責任者, Earth, Planets and Space
  • 2019年03月 - 2020年03月, Research Fellow, ニュージーランド国カンタベリ大学
  • 2014年07月 - 2018年06月, 編集委員, 日本火山学会
  • 2016年04月 - 2017年03月, Research Fellow, ニュージーランド国カンタベリ大学
  • 2013年07月 - 2016年06月, 60周年記念事業委員, 日本火山学会
  • 2012年 - 2013年, ゲスト編集委員, 日本地質学会
  • 2008年10月 - 2012年09月, 火山部会幹事(行事委員), 日本地質学会
  • 2010年07月 - 2012年06月, 事業委員, 日本火山学会

研究者からのメッセージ

  • (研究者からのメッセージ)

    主な研究テーマ

    1)火山の地質学的研究(Geologic study of volcanoes)

    2)火山の岩石学的研究(Petrologic study of volcanoes)

    3)火山の古地磁気学的研究(Paleomagnetic study of volcanoes)


    1)国内外の火山地域で現地調査を行い、堆積物や地形から、火山の噴火史や形成史を復元する基礎研究を行っています。国内は北海道・東北・関東・九州、海外はニュージーランド・カメルーン・ロシア。


    2)現地で採取した火山噴出物を持ち帰り、顕微鏡観察や化学組成分析を行って、火山の本質とも言えるマグマの発生・進化過程を明らかにします。最近は、マグマ片を含まない水蒸気噴火にも着目中。


    3)新しいテーマです。古地磁気学を用いて、噴出物の熱履歴や残留磁化方位を明らかにし、火山噴火のプロセスをこれまでにない高解像度で復元する研究手法を開発しています。


    以上の研究では、噴火の防災対策や将来予測にも貢献しうる成果を得ることができます。


    共同研究可能技術:地質調査、岩石学的分析、古地磁気学的分析

    研究設備:岩石薄片作成と顕微鏡観察設備(立軸平面研削機など)、粒度分析(ふるい振とう機・レーザ回折散乱式粒子径分布測定装置など)、XRF・SEM-EDS・ICP-MS分析とその前処理に必要な機器類(マルチビーズショッカーなど)、岩石古地磁気分析機器類(自動置換型スピナー磁力計・タンブラー式交流消磁着磁装置など)

■研究活動情報

受賞

  • 2025年05月, 学生優秀論文賞(受賞論文の共著、指導), Evolution of a large-scale phreatoplinian eruption: Constraints from the 40 ka caldera-forming eruption of Kutcharo volcano, eastern Hokkaido, Japan, J Volcanol Geotherm Res, 452, 108125., 日本火山学会
    柴田翔平
  • 2025年03月, Highlighted Papers of 2024, Paleomagnetic study of the 30 ka Aira caldera-forming eruption and 60–45 ka Iwato pyroclastic flow deposits, southern Kyushu, Japan, Earth, Planets and Space (EPS)
    長谷川健;望月伸竜;渋谷秀敏;西原歩;楠稚枝;柴田翔平;岡田誠;西来邦章;佐藤勇輝
  • 2024年09月, 研究奨励賞(受賞論文の共著、指導), 福島県南部,二岐山火山の噴火史とマグマ供給系. 地質学雑誌, 129, 307–324., 日本地質学会
    渡部将太
  • 2023年05月, 論文賞, 北海道東部,摩周火山の7.6ka カルデラ形成噴火過程:地質学・岩石学・古地磁気学的手法による高分解能推移復元とLow aspect ratio ignimbrite(LARI)の認定, 日本火山学会
    長谷川 健;柴田翔平;小林哲夫;望月伸竜;中川光弘;岸本博志
  • 2021年09月, 研究奨励賞(受賞論文のCorresponding author), 栃木県北部,余笹川岩屑なだれ堆積物の層序・年代と運搬過程. 地質学雑誌,126, 293-310., 日本地質学会
    菊地瑛彦
  • 2008年09月, 研究奨励賞, 北海道東部,阿寒カルデラ周辺の前-中期更新世火砕堆積物の層序, 地質学雑誌, 113, 53-72., 日本地質学会
    長谷川健

論文

  • Preface: The 6th International Conference on Environmental Resources Management (ICERM) 2024
    Djati Mardiatno; Sayantan Das; Takeshi Hasegawa; Annisa Triyanti; Tsung-Yi Lin; Dian Nuraini Melati; Anabelle Moatty; Kyaw Zaya Htun, Anthropogenic pressure and climate change are the main issues of environmental degradation, posing significant challenges to sustainable landscape [1,2]. These issues are recognized as major global risks with long-lasting consequences [3]. Landscape management is an integrated approach that may be helpful to address these issues by combining policies and practices to address environmental degradation and promote sustainable land use planning [4]. This approach plays an important role in achieving sustainable livelihoods by integrating multiple objectives such as ecological, economic and social [5,6]. Proper landscape management can lead to numerous ecological benefits, including improved land restoration, increased forest cover, enhanced ecosystem services, and maintain the biodiversity [5,6,7]. In the economic and social context, land management can be beneficial for promoting food security, reducing vulnerability to climate change, and improving welfare [5,6,7].

    Department of Environmental Geography, the Faculty of Geography Universitas Gadjah Mada, has a long history of conducting research on environmental management. The concept of sustainable land management aligns with the department’s research framework, which emphasizes the analysis of land, water, social, and economic factors to improve population welfare and reduce risk. To address current issues and discuss efforts related to sustainable land management, the department is organizing the 6th International Conference on Environmental Resources Management (ICERM) to showcase the latest scientific advancements.

    List of Conference Committee is available in this pdf., IOP Publishing
    IOP Conference Series: Earth and Environmental Science, 2025年02月20日, [査読有り]
  • Cooling timescale and process of welded facies of Youngest Toba Tuff, North Sumatra, Indonesia
    Shohei Shibata; Gabriela Nogo Retnaningtyas Bunga Naen; Yasuaki Kaneda; Indranova Suhendro; Chie Kusu; Takeshi Hasegawa, ラスト(シニア)オーサー, Abstract

    The 74 ka Youngest Toba Tuff (YTT) super-eruption is one of the largest caldera-forming eruptions on Earth. Thick welded facies (~100 m) of the YTT are exposed 30 km northwest of the source caldera. In this outcrop, an entablature of columnar joints, consisting of multiple domains can be well observed. The domain is cracked by a vertical master joint (cooling plane), from which a chilled margin and many columnar joints developed laterally. In this study, the paleomagnetic method was applied to evaluate the cooling history and genetic processes of the YTT welded facies. Oriented samples were collected from both the cooling plane (CP) and the interior part of the domain (ID), and all samples were subjected to a thermal demagnetization experiment. Samples from CP and ID show slightly different directions that can be confirmed by the significance test. Compared to CP, the characteristic remanent magnetization (ChRM) mean direction of ID shows shallower inclination and northern declination (Dm=357.5°, Im=2.2°, α95=2.5°) that is consistent with previous data of YTT. The mean angular difference of CP and ID is calculated to be 3.2° ± 2.1°. To generate such an angular difference would take 22.8 ± 15.2 years, assuming the fastest changing rate of geomagnetic secular variation (0.14°/year). This suggests that there exists a time lag of tens of years for acquiring thermal magnetization between CP and ID. Temperature profiles of YTT calculated using the conductive cooling model support the result that the interior part of the ignimbrite remained hot at ~ 600 °C for 30 years after deposition. Based on these findings, we conclude that the slight difference in paleomagnetic directions indicates heterogeneity in cooling timescale between quenched (CP) and slowly cooled (ID) portions within thick the welded YTT., IOP Publishing
    IOP Conference Series: Earth and Environmental Science, 2025年02月20日, [査読有り]
  • Petrogenetic relationship of pre-caldera and caldera-forming magmas from Maninjau volcano, West Sumatera, Indonesia
    Yasuaki Kaneda; Indranova Suhendro; Shohei Shibata; Gabriela Nogo Retnaningtyas Bunga Naen; Festus Tongwa Aka; Takeshi Hasegawa, ラスト(シニア)オーサー, Abstract

    The 220–250 km3 (VEI 7) caldera-forming eruption of Maninjau (West Sumatra, Indonesia) in 52 ±3 ka played a major role for changing the landscape in the Padang Volcanic Field. Besides forming thick and widespread ignimbrite plateau (especially in the vicinity of Bukttinggi), the eruption successfully exposed the stratigraphy of pre-caldera rocks which predominantly constructed of lava (hereafter referred to as somma lava). Since our knowledge regarding the relationship between the pre-caldera somma lavas and silicic caldera-forming activity is lacking, we aimed to study the petrological characteristics of these eruptive materials. Somma lavas are mostly classified as medium-K andesite to dacite (SiO2 = 57–64 wt.%) except for one rhyolitic sample (SiO2 = 77 wt.%). Although whole-rock chemistry of somma lavas largely shows coherent compositional trends that a priori suggest mixing with caldera-forming magmas, there are considerable compositional gaps between them on some SiO2 against incompatible-element (e.g., Sr and Zr) diagrams. Rayleigh fractionation models suggest that it is difficult to generate the caldera-forming silicic magma by differentiation of somma lava magma. Considering the incoherences of petrological and chronological features between Maninjau somma lavas and ignimbrites, we suggest that the caldera-forming large silicic magma evolved as an independent system after the termination of pre-caldera magmatism., IOP Publishing
    IOP Conference Series: Earth and Environmental Science, 2025年02月20日, [査読有り]
  • Volcanic history and magma systems of Lake Monoun Polygenetic Maar, Noun Plain, Western part of the Cameroon Volcanic Line: Constraints from stratigraphy, chronology and geochemistry
    Linus Anye Nche; Takeshi Hasegawa; Festus Tongwa Aka; Takeshi Ohba; George Teke Mafany; Károly Németh; Yasuo Miyabuchi; Yasuaki Kaneda; Asobo Nkengmatia Elvis Asaah; Patrick Mendi Wajiba; Caroline Neh Ngwa; Joseph Legrand Tchop; Pauline Wokwenmendam Nguet; Ntepe Nfomou; Cheo Emmanuel Suh; Wilson Yetoh Fantong; Farouk Oumar Mouncherou, Elsevier BV
    Journal of Volcanology and Geothermal Research, 2025年01月, [査読有り]
  • Paleomagnetic study of the 30 ka Aira caldera-forming eruption and 60–45 ka Iwato pyroclastic flow deposits, southern Kyushu, Japan
    Takeshi HASEGAWA; Nobutatsu Mochizuki; Hidetoshi Shibuya; Ayumu Nishihara; Chie Kusu; Shohei Shibata; Makoto Okada; Kuniaki Nishiki; Yuki Sato, 筆頭著者
    Earth, Planets and Space, 2024年12月, [査読有り]
  • Application of a recently developed method of oriented drill coring to accumulative tephra layers: identification of the Matuyama–Brunhes geomagnetic reversal in Akan caldera-forming eruption deposits
    Takeshi Hasegawa; Chie Kusu; Makoto Okada; Aoi Hiratsuka; Kuniaki Nishiki; Yuki Sato; Masaru Koshigai; Takuya Matsuzaki; Yuhji Yamamoto, 筆頭著者, Abstract

    We adapted a recently developed technique of oriented drill coring (100 m in depth) for paleomagnetic measurements, including additional techniques such as half-cutting of the drill cores and accurate cube sampling using an apparatus that precisely guides the cube into the half-cut drill core surface. Our techniques were successfully applied to sequential tephra layers (including loess) at Akan Quaternary caldera volcano in eastern Hokkaido, Japan. Directions of remanent magnetization for a total of 129 specimens were measured by Spinner magnetometer with thermal and alternating field demagnetizations. We detected clear Matuyama–Brunhes geomagnetic reversal between the depths of 20.59 m and 21.30 m, where inclinations change from 65.1 to –44.3°. With these techniques, we can in future obtain useful geologic information (e.g., radiometric ages and absolute paleo-intensities) from volcanic rocks around the Matuyama–Brunhes boundary in Akan volcano. This will clarify more detailed processes of the geomagnetic polarity transition. Our study demonstrates the utility of oriented drill cores from successive tephra and loess layers for high resolution investigate of continuous paleo-geomagnetic records. The new techniques can be adopted to other geological fields on Earth, like in studies of marine sediments, providing continuous paleomagnetic direction data from drill core.

    Graphical Abstract, Springer Science and Business Media LLC
    Earth, Planets and Space, 2024年10月31日, [査読有り]
  • マグマ噴出量階段図の標準的な作成手法の提案と有珠山での作成例
    中川光弘; 松本亜希子; 宮縁育夫; 長谷川健; 古川竜太; 上澤真平; 長井雅史
    火山, 2024年10月, [査読有り]
  • 第8回IAVCEI陥没カルデラワークショップ研究集会報告
    下司 信夫; 後藤 芳彦; 金子 克哉; 三浦 大助; 長谷川 健; 富島 千晴; 柴田 翔平
    火山, 2024年07月, [査読有り]
  • Evolution of a large-scale phreatoplinian eruption: Constraints from the 40 ka caldera-forming eruption of Kutcharo volcano, eastern Hokkaido, Japan
    Shohei Shibata; Takeshi Hasegawa
    Journal of Volcanology and Geothermal Research, 2024年06月, [査読有り]
  • 北海道南西部,濁川火山カルデラ噴火の軽石礫に認められる高Ba異常とその成因:岩石組織および化学組成からの検討
    金田泰明; 長谷川健; 井村 匠, The Geological Society of Japan
    地質学雑誌, 2023年12月22日, [査読有り]
  • Paleomagnetism and paleomagnetic dating to large volcanic bombs: an example from the historical eruption of Azuma–Jododaira volcano, NE Japan
    Takeshi Hasegawa; Bunta Kikuchi; Shibata Shohei; Yuhji Yamamoto; Takumi Imura; Masao Ban; Kae Tsunematsu; Chie Kusu; Makoto Okada; Tsukasa Ohba, 筆頭著者, Abstract

    Vulcanian activity is one of the most common eruption styles of arc andesitic volcanism on Earth. It ejects and deposits volcanic bombs around the source crater. Although paleomagnetic studies of volcanic bombs are limited, such studies can potentially provide more opportunities for high-resolution paleomagnetic dating of volcanic activity. In this study, paleomagnetic dating was applied to large (> 1 m) volcanic bombs around active craters in the Azuma volcano group, NE Japan. Oriented samples were collected from the interior parts of five large volcanic bombs situated on gentle slopes, a few hundred meters from the source crater. More than six core samples were collected from each bomb and all samples were subjected to a range of rock magnetic experiments, including anisotropy of magnetic susceptibility (AMS) and thermal/alternating field demagnetization (THD/AFD) analyses. The Characteristic Remanent Magnetization (ChRM) directions for specimens from all bombs were well-defined, have small α95 (< 2.5º), and are in close agreement with each other. Comparing our measured overall mean direction (Dm = 355.5º, Im = 49.8º, α95 = 1.6º) with modeled geomagnetic field estimates and a reference secular variation curve for this area (using MATLAB-based archaeomagnetic dating tool), we suggest that the volcanic bombs were produced in the historical Meiji period (1893–1895 CE) eruption. In addition, a combination of the data of ChRM, AMS, thermomagnetic analyses, hysteresis measurement, and XRF analysis indicates that the volcanic bombs were derived from a plug of lava in the conduit under the solidification point (ca. 800 °C), but above the Curie point of the titanomagnetite remanence carrier (around 300 °C). We show that volcanic bombs can be powerful for paleomagnetic dating if certain sampling conditions, such as quantity, situation, size and portion are satisfied.

    Graphical Abstract, Springer Science and Business Media LLC
    Earth, Planets and Space, 2023年11月16日, [査読有り]
  • 福島県,吾妻―浄土平火山の1893年明治噴火はマグマ放出を伴って いた:燕沢火口列周辺に分布する巨大な火山弾の古地磁気年代測定 による推察
    長谷川 健; 菊池 文太; 柴田 翔平; 井村 匠; 伴 雅雄; 常 松佳恵; 山本 裕二; 大場 司; 鈴木和馬; 戸丸淳晴; 楠 稚枝; 岡田 誠, 筆頭著者
    火山, 2023年09月, [査読有り]
  • Multi-method constraints on the age and timescale of silicic small-volume eruptions of Puketerata Volcanic Complex, Taupō Volcanic Zone, New Zealand
    Szabolcs Kósik; Takeshi Hasegawa; Martin Danišík; Károly Németh; Makoto Okada; Bjarne Friedrichs; Axel K. Schmitt, Abstract

    Accurate dating of young eruptions from explosive volcanoes is essential for forecasting future eruptions and for defining the hazardscape of volcanic fields. However, precise dating of Quaternary eruptions is often challenging due to limited number of applicable dating methods or lack of datable eruptive phases. Moreover, small volume eruptions (e.g., monogenetic type), despite their significance on regional scale, have traditionally deserved less attention than their large volume counterparts. Puketerata is a maar-lava dome complex in the central Taupō Volcanic Zone (New Zealand), encompassing mafic and silicic phreatomagmatic eruptions with well-preserved pyroclastic deposits sourced from closely spaced vents. Its most recent activity is estimated to ca. 16 ka based on medial and distal stratigraphic surveys. Here, we carried out two independent age determinations and an additional paleomagnetic analysis on the volcanic succession of the Puketerata maar-lava dome complex with an aim to unravel the timing of volcanic activity. Combined U-Th disequilibrium and (U-Th)/He dating of zircon from two lava domes yielded eruption ages of 11.3 ± 2.6 ka and 11.3 ± 1.7 ka, which are concordant with the radiocarbon ages of 11.3–11.7 ka obtained on charcoal from the base of the pyroclastic sequence. Paleomagnetic data on the lavas from the two lava domes suggest at least ~ 100 years difference between their emplacements. Our geochronological results and new stratigraphic observations suggest that the volcanic/magmatic history of the Puketerata is complex with multiple eruptions within a small, confined area, where the most recent eruptions occurred only at ca. 11.5 ka, which is significantly younger than previously thought. This provides an additional datum for volcanic hazards assessment and stratigraphic correlations in New Zealand.

    Graphical Abstract, Springer Science and Business Media LLC
    Earth, Planets and Space, 2023年07月12日, [査読有り]
  • IAVCEI(国際火山学地球内部化学協会)2023年大会参加報告(その2):巡検と学会参加の感想
    松本恵子; コンウェイ クリス; 畑 真紀; 伊藤久敏; 岩橋くるみ; 片岡香子; 森田雅明; 西原 歩; 三反畑修; 渡部将太; 山﨑誠子; 長谷川健, ラスト(シニア)オーサー, 内部査読
    火山, 2023年06月, [査読有り]
  • IAVCEI(国際火山学地球内部化学協会)2023年大会参加報告(その1):セ ッションとワークショップの概況               
    長谷川健; 松本恵子; 橋本武志; 畑 真紀; 岩橋くるみ; 無盡真弓; 村松 弾; 大橋正俊; 三反畑修; 嶋野岳人; 田中 良; 安田裕紀, 筆頭著者, 内部査読
    火山, 2023年06月, [査読有り]
  • Varying stages of ecological succession in lakes subdivided by volcanic eruptions at Akan Caldera, Japan
    Isamu Wakana; Yasuro Kadono; Jotaro Urabe; Yuki Tamura; Yoshifusa Suzuki; Hiroyuki Yamada; Yoichi Oyama; Keiji Wada; Takeshi Hasegawa; Masashi Ohara, Abstract

    Ecological succession within lakes generally proceeds as eutrophication and shallowing occur and the aquatic biota of the lakes is altered. The eutrophication rate depends on the lake size and the area and fertility of the watershed. If the watershed fertility of several different lakes is equivalent and the lakes’ formation time and initial environment are similar, the trophic status of each lake is expected to increase over time depending on the ratio of the watershed area to lake size. To test this supposition, we surveyed the topography and water quality of 10 lakes of varying sizes in Akan Caldera, Japan, which were formed thousands of years ago by fragmentation due to volcanic eruptions within the caldera. The ratio of the accumulated watershed area to lake size was positively correlated with total phosphorus concentration, an indicator of trophic status, and lake types were classified as oligotrophic, mesotrophic, eutrophic, and dystrophic. In addition, 21 species of macrophytes were found in the lakes, and the species composition of each lake was divided into five types corresponding to combinations of the lake types. The discovery of such diversity in a group of lakes with a similar origin paves the way for new comparative studies., Springer Science and Business Media LLC
    Hydrobiologia, 2023年04月23日, [査読有り]
  • 福島県南部,二岐山火山の噴火史とマグマ供給系
    渡部 将太; 長谷川 健; 小畑 直也; 豊田 新; 今山 武志, The Geological Society of Japan
    The Journal of the Geological Society of Japan, 2023年04月06日, [査読有り]
  • Paleomagnetic constraint of the age and duration of the Taupō Eruption, New Zealand
    Takeshi Hasegawa; Annika Greve; Darren M. Gravley; Chie Kusu; Yasuaki Kaneda; Shohei Shibata; Makoto Okada; Szabolcs Kósik; Nobutatsu Mochizuki; Gillian Turner, 筆頭著者
    Earth, Planets and Space, 2023年02月
  • 栃木県北部,塩原カルデラ噴出物の編年とマグマ変遷
    西野佑紀; 長谷川健; 伊藤久敏; 菊地瑛彦; 大井信三, 責任著者
    地質学雑誌, 2023年02月, [査読有り]
  • Geological, geophysical and geochemical constraints on the time-space evolution of Akan composite caldera, Hokkaido, Japan
    Hasegawa, T; Nakagawa, M; Kamiyama, H; Yamamoto, A, 筆頭著者
    Frontiers in Earth Sciences, 2022年09月, [査読有り]
  • The complexities of assessing volcanic hazards along the Cameroon Volcanic Line using spatial distribution of monogenetic volcanoes
    Christoph Schmidt; Christian Laag; Melody Whitehead; Jörn Profe; Festus Aka; Takeshi Hasegawa; Gabor Kereszturi
    Journal of Volcanology and Geothermal Research, 2022年07月, [査読有り]
  • No evidence for tephra in Greenland from the historic eruption of Vesuvius in 79 CE: implications for geochronology and paleoclimatology
    Gill Plunkett; Michael Sigl; Hans F. Schwaiger; Emma L. Tomlinson; Matthew Toohey; Joseph R. McConnell; Jonathan R. Pilcher; Takeshi Hasegawa; Claus Siebe, Abstract. Volcanic fallout in polar ice sheets provides important opportunities to date and correlate ice-core records as well as to investigate the
    environmental impacts of eruptions. Only the geochemical characterization of volcanic ash (tephra) embedded in the ice strata can confirm the source
    of the eruption, however, and is a requisite if historical eruption ages are to be used as valid chronological checks on annual ice layer
    counting. Here we report the investigation of ash particles in a Greenland ice core that are associated with a volcanic sulfuric acid layer previously
    attributed to the 79 CE eruption of Vesuvius. Major and trace element composition of the particles indicates that the tephra does not derive from
    Vesuvius but most likely originates from an unidentified eruption in the Aleutian arc. Using ash dispersal modeling, we find that only an eruption
    large enough to include stratospheric injection is likely to account for the sizable (24–85 µm) ash particles observed in the Greenland
    ice at this time. Despite its likely explosivity, this event does not appear to have triggered significant climate perturbations, unlike some other
    large extratropical eruptions. In light of a recent re-evaluation of the Greenland ice-core chronologies, our findings further challenge the previous
    assignation of this volcanic event to 79 CE. We highlight the need for the revised Common Era ice-core chronology to be formally accepted by the wider
    ice-core and climate modeling communities in order to ensure robust age linkages to precisely dated historical and paleoclimate proxy records., Copernicus GmbH
    Climate of the Past, 2022年01月18日, [査読有り]
  • Geochemical composition of dykes along the Cameroon Line (CL): Petrogenesis and similarities with the Central Atlantic Magmatic Province
    Asobo Nkengmatia Elvis Asaah; Tetsuya Yokoyama; Hikaru Iwamori; Festus Tongwa Aka; Jules Tamen; Takeshi Kuritani; Tomohiro Usui; Takeshi Hasegawa; Eric Martial Fozing, We report whole-rock geochemistry and Sr–Nd–Pb isotopic compositions of mafic dykes intruded in the Precambrian granito-gneissic basement complex, exposed at Nyos, Batibo, Dschang and Foumban on the Cameroon Line. The dykes are alkaline (Batibo), transitional (Foumban), and subalkaline (Nyos, Batibo and Dschang) with SiO2 of 45–54 wt% and MgO of 2–9 wt%, similar to dykes reported in other areas of the Cameroon Line (CL) and the Central Atlantic Magmatic Province (CAMP). The abundances of rare earth elements (REE) and the Primitive Mantle normalised patterns for the Nyos, Batibo and Dschang dykes are similar to those of MORB, indicating that the dykes formed at shallower depths by a higher degree of partial melting relative to the Foumban dykes and the alkaline lavas of the CL. The transitional basaltic dykes with steeper REE patterns have their sources at deeper levels in the lithospheric mantle, possibly the garnet-spinel transition zone and were generated by a lower degree partial melting of the lithospheric and plume components. The Nyos and Batibo subalkaline dykes show similar isotopic compositions with a spectrum extending from depleted (DMM-like) to enriched (EM1-like) mantle, indicating the similarity in their source components. The Dschang dykes show distinct isotopic characteristics with relatively unradiogenic Nd-Pb isotope compositions compared to the Batibo and Nyos dykes. The Foumban transitional dykes with characteristic wide ranges in Sr-Nd-Pb isotopic compositions reveal varying contributions from enriched mantle components (EM1 and EM2) in addition to its plume signature similar to those of CL lavas. The Nyos and Batibo dykes alongside other dykes on the CL have low TiO2 abundances (<2 wt%), negative PM-normalised Nb-anomalies, and moderately to strongly enriched REE patterns, and isotopic composition that overlaps with those of CAMP, suggesting a similar lithospheric origin., Elsevier BV
    Geochemistry, 2022年01月, [査読有り]
  • High–μ signature in lavas of Mt. Oku: Implications for lithospheric and asthenospheric contributions to the magmatism of the Cameroon Volcanic Line (West Africa)
    A.N.E. Asaah; T. Yokoyama; H. Iwamori; F.T. Aka; T. Kuritani; T. Usui; J. Tamen; M. Gountié Dedzo; B. Chako-Tchamabé; T. Hasegawa; L.A. Nche; T. Ohba, This study presents geochemical data for mafic lavas from Mt. Oku to investigate the mantle source for Mt. Oku lavas and regional variations in isotopic ratios along the Cameroon Volcanic Line (CVL). The investigated mafic lavas present trace element and isotope signatures akin to ocean island basalts (OIB) and cover the entire range of the CVL. Major and trace element compositions of the studied lavas indicates that they have undergone fractionation of olivine + clinopyroxene + Fe-Ti oxide ± Cr–spinel with insignificant crustal contamination. The lavas were generated by <2% partial melting from a heterogeneous source containing less than 4% garnet. Major and trace elements abundances indicate the presence of hydrous minerals indicative of modal metasomatism. The highest value of radiogenic 206Pb/204Pb (20.7) so far measured along the CVL is reported in this study. The isotopic features of the lavas suggest that the HIMU signatures are dominantly inherited from the asthenosphere (primary source) and melting of enriched components hosted in the subcontinental lithospheric mantle (SCLM; secondary source). Lavas from Mt. Oku present more comprehensive ranges of Sr–Nd–Pb isotopic composition than those from the continent-ocean-boundary (COB). The isotopic composition of Mt. Oku lavas with 206Pb/204Pb > 19.5 differs from those of the COB but are similar to FOZO. The isotopic composition of Mt. Oku lavas (87Sr/86Sr = 0.7030–0.7036, 143Nd/144Nd = 0.5127–0.5129, 206Pb/204Pb = 17.9–20.7) suggest that the lavas are the result of contributions from the asthenosphere and the SCLM. Using a combination of Sr–Nd–Pb isotope display on a 3D plot and Sm/Yb, we identify four essential components denoted; A, B, C and D involved in the petrogenesis of Mt. Oku lavas and the approximate melting depth. While A and B are from the asthenosphere with HIMU mantle flavour, C and D owe their origin from the SCLM with EM1 and DMM characteristics, respectively. Although depleted in Sr-Nd isotopes, D is radiogenic in 206Pb/204Pb, indicating the influence of metasomatism. Therefore, the petrogenesis of Mt. Oku lavas involves the mixing of at least three mantle end-members: HIMU–DMM–EM1. The “fanning” of samples from”A" towards the other components (B, C and D) indicates a HIMU–like end–member dominance in Mt. Oku magmatism. Considering the geophysical studies on mantle convection and plumes, we have developed a schematic model that explains the petrogenesis of the CVL lavas. The continuous spectrum from relatively depleted to HIMU characteristics of CVL lavas is associated with the progressive change in source components (i) SCLM with ± pockets of enriched metasomes to (ii) SCLM + asthenosphere sources and finally to (iii) typically asthenospheric source material ± pockets of enriched metasomes. Lavas derived from stage (i) exhibit geochemical variability involving DMM–like and EM1–like signatures. The magma generated at Stage (iii) is dominated by the HIMU mantle component and accounts for over 85% of CVL lavas., Elsevier BV
    Lithos, 2021年11月, [査読有り]
  • A tephra-based approach to calibrating relative geomagnetic paleointensity stacks to absolute values
    Nobutatsu Mochizuki; Satomu Fujii; Takeshi Hasegawa; Yuhji Yamamoto; Tadahiro Hatakeyama; Daisuke Yamashita; Makoto Okada; Hidetoshi Shibuya, Elsevier BV
    Earth and Planetary Science Letters, 2021年10月, [査読有り]
  • 北海道東部,摩周火山の7.6 kaカルデラ形成噴火過程:地質学・岩石学・古地磁気学的手法による高分解能推移復元とLow aspect ratio ignimbrite(LARI)の認定
    長谷川健; 柴田翔平; 小林哲夫; 望月伸竜; 中川光弘; 岸本博志, 筆頭著者, Based on detailed fieldwork, petrological and paleomagnetic investigations, we present a revised stratigraphy of deposits from the 7.6 ka eruption at Mashu volcano and the formation process of its summit caldera, eastern Hokkaido, Japan. As previously described, the eruption products consist of an initial phreatomagmatic unit (Ma-j) and the overlying three pumice-fall layers (Ma-i, -h, and -g), which are in turn overlain by pyroclastic-flow deposits (Ma-f). In the present study, we divide Ma-f into 4 subunits: Ma-f1/2, Ma-fAc, Ma-f3a and Ma-f3b in descending order. Ma-f3b is a valley-ponding, pumice-flow deposit with limited distribution. Ma-f3a comprises clast-supported facies (fines-depleted ignimbrite: FDI) and matrix-supported (normal ignimbrite) facies, the two changing across topography. The FDI is characterized by a gray, fines-depleted, lithic-breccia-rich layer with materials incorporated from the substrate. Impact sag structures from large (>50 cm) dacite ballistic blocks were recognized at the base of the Ma-f3a within 10 km from the source. Ma-fAc is a minor eruption unit consisting of accretionary lapilli. Ma-f1/2 is a most voluminous (8.8 km3), widely distributed and weakly stratified ignimbrite. Both Ma-f3a and Ma-f1/2 can be classified as “low aspect ratio ignimbrite (LARI)”. Dacite lithic fragments are ubiquitously observed throughout the sequence and are not considered to be juvenile; they have distinctly different chemical compositions from the pumice fragments in the early pumice-fall (Ma-g~Ma-i) and pyroclastic-flow (Ma-f3b) deposits, but those of pumice clasts in the late pyroclastic-flow units (Ma-f3a and Ma-f2) lie between the two on a FeO*/MgO vs. SiO2 diagram. The 7.6 ka caldera-forming eruption of the Mashu volcano was initiated by Plinian fall (Ma-j~-g), and then, a small-volume high aspect ratio ignimbrite (Ma-f3b) was deposited by a valley-confined pyroclastic flow that was generated by partial column collapse. After that, a violent pyroclastic flow was generated probably during a strong explosion of a dacite lava edifice on the summit of Mashu volcano. This flow emplaced Ma-f3a. The caldera collapse that followed the explosion generated a climactic pyroclastic flow that emplaced Ma-f1/2. Ma-f3a flow was extremely fast. Ma-f1/2 flow was related to sustained flow due to low settling velocity and high discharge volume. These are supported by field observations and numerical simulation that shows the ability of the flow to surmount high topographic obstacles and spread widely. The 7.6 ka caldera-forming process of Mashu volcano was driven not only by subsidence of roof block but also by violent explosions., 特定非営利活動法人 日本火山学会
    火山, 2021年09月, [査読有り]
  • ヤチカンバ花粉の識別と北海道東部の西別湿原における6500年前以降の植生史               
    吉川昌伸; 鈴木三男; 佐藤雅俊; 小林和貴; 長谷川健; 吉川純子; 戸田博史
    植生史研究, 2021年02月, [査読有り]
  • Lithostratigraphy and geochemistry of Aojiki volcano and Sumiyoshiike and Yonemaru maars, Kamo Volcanic Field (Southern Kyushu), Japan
    Nche, L.A; Hasegawa, T; Aka, F.T; Kobayashi, T; Nemeth, K; Asaah, A.N.E; Kaneda, Y; Nishihara, A; Etakah, B-T.E; Lebga, A.K; Tiabou, A.F; Ngwa, C.N; Suh, C.E, 責任著者
    Journal of Volcanolgy and Geothermal Research, 2020年12月, [査読有り]
  • Repetitive duality of rhyolite compositions, timescales, and storage and extraction conditions for Pleistocene caldera-forming eruptions, Hokkaido, Japan               
    Pitcher, B; Gualda, G.A; Hasegawa, T
    Journal of Petrology, 2020年12月, [査読有り]
  • Major/trace elements and Sr–Nd–Pb isotope systematics of lavas from lakes Barombi Mbo and Barombi Koto in the Kumba graben, Cameroon volcanic line: Constraints on petrogenesis
    A.N.E. Asaah; T. Yokoyama; F.T. Aka; H. Iwamori; T. Kuritani; T. Usui; M. Gountie Dedzo; J. Tamen; T. Hasegawa; E.M. Fozing; M.J. Wirmvem; A.L. Nche, 担当:化学分析, Elsevier {BV}
    Journal of African Earth Sciences, 2020年01月, [査読有り]
  • 栃木県北部,余笹川岩屑なだれ堆積物の層序・年代と運搬過程
    菊地瑛彦; 長谷川健, 責任著者
    地質学雑誌, 2020年, [査読有り]
  • Eruption history and petrogenesis of rocks from Nyos volcano (NW Cameroon): Evidence from lithostratigraphy and geochemistry
    Takeshi Hasegawa; Festus Tongwa Aka; Yasuo Miyabuchi; Linus Anye Nche; Tetsuo Kobayashi; Katsuya Kaneko; Asobo Nkengmatia; Elvis Asaah; Boniface Kankeu; Issa; Takeshi Ohba; Minoru Kusakabe; Joseph Victor Hell, 筆頭著者, 筆頭, ELSEVIER SCIENCE BV
    Journal of Volcanology and Geothermal Research, 2019年06月, [査読有り]
  • Upper Triassic mafic dykes of Lake Nyos, Cameroon (West Africa) I: K-Ar age evidence within the context of Cameroon Line magmatism, and the tectonic significance
    Festus Tongwa Aka; Takeshi Hasegawa; Linus Anye Nche; Asobo Nkengmatia Elvis Asaah; Mumbfu Ernestine Mimba; Isidore Teitchou; Caroline Ngwa; Yasuo Miyabuchi; Tetsuo Kobayashi; Boniface Kankeu; Tetsuya Yokoyama; Gregory Tanyileke; Takeshi Ohba; Joseph Victor Hell; Minoru Kusakabe, The hydrodynamic fragmentation that formed Lake Nyos in northwest Cameroon did not only make it the most unpopular lake in the world from a gas disaster perspective, it also opened a rare and formidable window through which much of the geology of Cameroon can be studied in a single locality. The Cambrian quartz monzonite cliff excavated by the maar-forming explosion and exposed in its northeastern shore is intruded by mafic dykes, two of which we dated. Even though close to one another, the dykes are different in composition. The alkaline dyke yields a slightly older (Carnian) K-Ar fedspar age of 231.1 ± 4.8 Ma, while the sub alkaline dyke yields an age of 224.8 ± 4.7 Ma (Norian). Based on radioisotopic age data available over the last 48 years (347 data) for the Cameroon Line magmatism comprising eruptives and volcano-plutonic complexes, the Nyos dykes are way older than the Cameroon Line, and even pre-date the Lower Cretaceous initiation of west Gondwana fragmentation in Equatorial Atlantic domain. They would therefore not have been directly linked to the formation of the Cameroon Line. Alternatively, they might be associated with the development of intra-continental rift systems in West Central Africa that pre-dated west Gondwana breakup to form the Atlantic Ocean., Elsevier Ltd
    Journal of African Earth Sciences, 2018年05月01日, [査読有り]
  • Petrology of the 120 ka Caldera-Forming Eruption of Kutcharo Volcano, Eastern Hokkaido, Japan: Coexistence of Multiple Silicic Magmas and their Relationship with Mafic Magmas
    Matsumoto, A; Hasegawa, T; Nakagawa, M, 担当:現地調査・試料採取
    Journal of Petrology, 2018年04月, [査読有り]
  • 大規模カルデラ形成噴火と活動的後カルデラ火山:─北海道南西部,洞爺カルデラと有珠火山の地質概説および露頭紹介─
    長谷川 健; 松本 亜希子; 東宮 昭彦; 中川 光弘, 筆頭著者,

     Toya caldera, eastern Hokkaido, was formed approximately 110 ka, and has two post-caldera volcanoes, Nakajima and Usu volcano. Caldera-forming eruptions ejected a large-scale Toya pyroclastic flow, and related co-ignimbrite ash which covered a wide area in northern Japan. Usu volcano is one of the most active volcanoes in Japan, and has had repeated magmatic eruptions during historical time since AD 1663. The latest major eruption occurred in AD 2000. General geology and representative outcrops of eruptive deposits from Toya caldera and its post-caldera volcanoes are introduced, on the basis of a training field course at the 6th IAVCEI Collapse Caldera Workshop held in September 2016.

    , 公益社団法人 東京地学協会
    地學雜誌, 2018年, [査読有り]
  • Methods of Estimating the Durations of Super Large Eruptions Based on Pyroclastic Deposits
    Hasegawa Takeshi; Mochizuki Nobutatsu; Oiwane Hisashi, 筆頭著者, 筆頭, TOKYO GEOGRAPHICAL SOC
    JOURNAL OF GEOGRAPHY-CHIGAKU ZASSHI, 2018年, [査読有り]
  • 北海道東部,アトサヌプリ火山における水蒸気噴火の発生履歴:炭素年代および気象庁ボーリングコアからの検討
    長谷川健; 中川光弘; 宮城磯治, 筆頭著者, 筆頭, 一般社団法人 日本地質学会
    地質学雑誌, 2017年05月, [査読有り]
  • IAVCEI(国際火山学地球内部化学協会)2017年大会参加報告
    橋本 武志; 田中 良; 上澤 真平; 山田 大志; 長谷川 健; 小園 誠史; 萬年 一剛; 中道 治久; 隅田 まり; 鈴木 由希; 田島 靖久; 高木 朗充, 担当部執筆(解説・紹介), 特定非営利活動法人 日本火山学会
    火山, 2017年, [査読有り]
  • Superconductivity and Non-Fermi-Liquid Behavior in the Heavy-Fermion Compound CeCo1−xNixIn5
    Ryo Otaka; Makoto Yokoyama; Hiroaki Mashiko; Takeshi Hasegawa; Yusei Shimizu; Yoichi Ikeda; Kenichi Tenya; Shota Nakamura; Daichi Ueta; Hideki Yoshizawa; Toshiro Sakakibara, The effect of off-plane impurity on superconductivity and non-Fermi-liquid
    (NFL) behavior in the layered heavy-fermion compound CeCo$_{1-x}$Ni$_x$In$_5$
    is investigated by specific heat, magnetization, and electrical resistivity
    measurements. These measurements reveal that the superconducting (SC)
    transition temperature T$_c$ monotonically decreases from 2.3 K (x=0) to 0.8 K
    (x=0.20) with increasing x, and then the SC order disappears above x=0.25. At
    the same time, the Ni substitution yields the NFL behavior at zero field for
    x=0.25, characterized by the -ln T divergence in specific heat divided by
    temperature, C$_p$/T, and magnetic susceptibility, M/B. The NFL behavior in
    magnetic fields for x=0.25 is quite similar to that seen at around the SC upper
    critical field in pure CeCoIn$_5$, suggesting that both compounds are governed
    by the same antiferromagnetic quantum criticality. The resemblance of the
    doping effect on the SC order among Ni- , Sn-, and Pt-substituted CeCoIn5
    supports the argument that the doped carriers are primarily responsible for the
    breakdown of the SC order. The present investigation further reveals the
    quantitative differences in the trends of the suppression of superconductivity
    between Ce(Co,Ni)In$_5$ and the other alloys, such as the rates of decrease in
    T$_c$, dT$_c$/dx, and specific heat jump at T$_c$, d($\Delta$C$_p$/T$_c$)/dx.
    We suggest that the occupied positions of the doped ions play an important role
    in the origin of these differences.
    Journal of the Physical Society of Japan, 2016年09月15日, [査読有り]
  • Superconductivity and Non-Fermi-Liquid Behavior in the Heavy-Fermion Compound CeCo1-xNixIn5
    Otaka Ryo; Yokoyama Makoto; Mashiko Hiroaki; Hasegawa Takeshi; Shimizu Yusei; Ikeda Yoichi; Tenya Kenichi; Nakamura Shota; Ueta Daichi; Yoshizawa Hideki; Sakakibara Toshiro, 担当:化学分析
    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 2016年07月29日, [査読有り]
  • Evolution of the 120 ka caldera-forming eruption of Kutcharo volcano, eastern Hokkaido, Japan: Geologic and petrologic evidence for multiple vent systems and rapid generation of pyroclastic flow
    Takeshi Hasegawa; Akiko Matsumoto; Mitsuhiro Nakagawa, 筆頭著者, We investigated the eruptive sequence and temporal evolution of juvenile materials during the 120 ka Kutcharo pumice flow IV (Kp IV) eruption, which was the most voluminous (175 km(3): bulk volume) caldera-forming eruption of Kutcharo volcano. The eruptive deposits are divided into four units in ascending order. Unit 1 is widely dispersed and consists of silt-sized, cohesive ash. Unit 2 is a thin, moderately sorted pumice fall deposit with a restricted distribution and small volume (<0.2 km(3)). Unit 3, consisting of widely distributed ignimbrite, is the most voluminous. Unit 4 is also composed of pyroclastic flow deposits, but its distribution is limited to the northwest side of the caldera. Juvenile materials consist mainly of rhyolite pumice (74%-78% SiO2) associated with a minor amount of scoria (52%-73% SiO2) that are found only northwest of the caldera in Unit 3 and Unit 4. These scoriae can be classified on the basis of the P2O5 contents of their matrix glass into low-P, medium-P, and high-P types, which are almost entirely restricted to the lower part of Unit 3, Unit 4, and the upper part of Unit 3, respectively. These three types display distinct mixing trends with the rhyolitic compositions in SiO2-P2O5 variation diagrams. This evidence indicates that three distinct mafic magmas were independently and intermittently injected into the main body of silicic magma to erupt from the northwestern part of the magma system. Mafic injections did not occur in the southern part of the magma system. This petrologic evidence implies that the northwestern and southeastern flows of Unit 3 are heterotopic, contemporaneous products derived from multiple vent systems. Although Unit 2 was derived from an eruptive column, its volume is very small compared to Plinian fall deposits of typical caldera-forming eruptions. In our interpretation, the activity of the Kp IV eruption reached its climax rapidly, depositing Unit 3, without first producing a stable Plinian column. The presence of multiple vent systems could have allowed the system to bypass an initial eruptive stage with a stable Plinian column and begin its climactic stage, represented by Unit 3, rapidly. Multiple vents could have been the result of sequential injections of mafic magma in the early stages of the Kp IV eruption. (C) 2016 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH, 2016年07月, [査読有り]
  • Large scale explosive eruptions of Akan volcano, eastern Hokkaido, Japan: A geological and petrological case study for establishing tephro-stratigraphy and -chronology around a caldera cluster
    Takeshi Hasegawa; Mitsuhiro Nakagawa, 筆頭著者, Akan volcano, in eastern Hokkaido in the southern Kurile arc, occupies a rectangular caldera (24 x 13 km) with a long (1.7-0.2 Ma) and complex history. This paper combines tephrostratigraphy, tephrochronology, and petrological and geochemical evidence to elucidate the eruptive history and evolution of the caldera. Pyroclastic deposits from Akan caldera are divided into at least 40 "eruptive units", separated by paleosols, that constitute 17 "eruptive groups" (Ak1 to Ak17, in descending stratigraphic order) that are petrologically distinct and separated by indicators of longer dormancy periods such as thick (> 30 cm) paleosols and angular unconformities. The estimated volumes of most eruptive groups are less than 10 km(3) dense rock equivalent, and four groups (Ak2, Ak4, Ak7, and Ak13) are larger. Group Ak2, exceeding 50 km3, is the largest. Pyroclastic deposits from Akan caldera are intercalated with pyroclastic deposits from the adjacent Kutcharo caldera and distal air-fall ash layers from central Hokkaido, suggesting that caldera-forming episodes overlapped in central and eastern Hokkaido. Radiometric ages from these exotic deposits range from 1.46 to 0.21 Ma, indicating that caldera-forming eruptions occurred at Akan volcano for more than 1 million years at an average magma discharge rate of approximately 10(-1) km(3)/kyr. Juvenile materials in Akan caldera pyroclastics consist of dominantly aphyric, two-pyroxene dacite to rhyolite. They are characterized by a wide range of K2O compositions (0.8-2.8 wt.%) within a narrow range of SiO2 compositions (67-73 wt.%). Plots of SiO2 vs. K2O suggest that each eruptive group is the product of a distinct, ephemeral magma system rather than a single long-lived magma system. These magma systems appear to have been generated and erupted successively beneath the caldera for more than 1 million years. Each magma system thus appears to represent a relatively short period of activity, and they were separated by relatively long dormancy periods before the next magma system. In particular, a long dormancy of 400 kyr preceded eruptive group Ak2, which consists of the most voluminous and compositionally varied silicic magmas. (C) 2015 Elsevier Ltd and INQUA. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
    QUATERNARY INTERNATIONAL, 2016年03月, [査読有り]
  • 茨城県日立市,宮脇A・泉前遺跡から出土した黒曜石製石器の産地推定
    長谷川健; 猪狩俊哉; 大平達雄; 田切美智雄; 向井正幸; 和田恵治, 筆頭著者, 筆頭, 日本文化財科学会
    考古学と自然科学, 2016年02月, [査読有り]
  • 第5回陥没カルデラワークショップ報告
    長谷川健; 下司信夫; 石川敦代, 筆頭著者, 筆頭(解説・紹介), 特定非営利活動法人日本火山学会
    火山, 2015年06月, [査読有り]
  • 岩石学的特徴を利用した対比・同定の有効性:北海道東部,阿寒・屈斜路火山における大規模火砕流堆積物の露頭情報
    長谷川健; 中川光弘, 筆頭著者, 筆頭, 特定非営利活動法人日本火山学会
    火山, 2014年12月, [査読有り]
  • 安達太良火山,12万年前噴火(岳噴火)における噴火推移の復元:火口近傍露頭と山麓火砕流との対比による推察
    藤原健一郎; 長谷川健; 藤縄明彦, 責任著者, 連絡著者, 特定非営利活動法人日本火山学会
    火山, 2014年12月, [査読有り]
  • Possible Evolution of Antiferromagnetism in Zn-Doped Heavy-Fermion Superconductor CeCoIn5
    Yokoyama, M; Fujimura, K; Ishikawa, S; Kimura, M; Hasegawa, T; Kawasaki, I; Tenya, K; Kono Y; Sakakibara, T, 担当:化学分析
    J. Phys. Soc. Jpn., 2014年02月04日, [査読有り]
  • 北海道東部,釧路地域における樽前d降下火砕堆積物の発見とその意義
    長谷川健; 花岡正光; 古川竜太; 重野聖之; 七山太; 中川光弘; 安藤寿男, 筆頭著者, 筆頭, The Geological Society of Japan
    地質学雑誌, 2013年07月, [査読有り]
  • 東北日本,仙岩地熱地域南部,高倉火山の山体形成史とマグマ供給系
    中谷咲子; 長谷川健; 藤縄明彦; 照井肇子, 責任著者, 連絡著者, The Geological Society of Japan
    地質学雑誌, 2013年07月, [査読有り]
  • Calderas and Active Volcanoes in Central to Eastern Hokkaido
    Hasegawa, T; Nakagawa, M; Kishimoto, H, 筆頭著者, 筆頭
    Bull. Volcanol. Soc. Jpn., 2013年06月, [査読有り]
  • 北海道東部厚岸沿岸低地の完新世バリアーシステムと海水準変動の復元
    重野 聖之; 七山 太; 須藤 雄介; 嵯峨山 積; 長谷川 健; 安藤 寿男, 北海道東部沿岸,厚岸湾沿岸地域には,日本では珍しい現在でも活動的なバリアーシステムが存在している.その成立過程と現存する理由について,ボーリング試料を用いて堆 積学的手法,古生物学的手法ならびに炭素同位体年代を用いて検討した結果,以下の3点が明確となった.(1)厚岸湾沿岸低地に後氷期海進が到達したのが11400年前である.この当時の海面の高さは現在より50 m低かった.その後の後氷期海進によって,厚岸バリアーシステムが成立したのは8800年前であり,現在もバリアーシステムは維持されている.(2)厚岸低地においてバリアーシステムが現在も地形的に維持されている理由としては,5500年前から続く海面の停滞の影響が大きく,この時期に厚岸湖のカキ礁も上げ潮三角州上に 生成し始めたものと推測される.(3)現在のバリアーシステムが地形的に明瞭であるのは, 17世紀の巨大地震以降の1 cm/年に達する急激な地震性沈降による影響が大きい., 一般社団法人 日本地質学会
    地質学雑誌, 2013年, [査読有り]
  • 樽前山B噴気孔群で見られた高温ガス噴出現象
    長谷川 健; 宮村 淳一; 伏谷 祐二; 高橋 裕二, 筆頭著者, 筆頭, 一般社団法人 日本地質学会
    地質学雑誌, 2013年, [査読有り]
  • The eruption history and silicic magma systems of caldera-forming eruptions in eastern Hokkaido, Japan
    Takeshi Hasegawa; Mitsuhiro Nakagawa; Hiroshi Kishimoto, 筆頭著者, The eruptive history and magma systems of large-scale explosive eruptions (VEI>5) in eastern Hokkaido, Japan, are reviewed on the basis of recently reported high-resolution tephrostratigraphy. More than 70 large-scale explosive eruptions have been recorded from the Akan, Kutcharo, Atosanupuri, and Mashu caldera volcanoes in the past 1.7 Ma. The total tephra volume of these eruptions is estimated to be approximately 1000 km(3). The discharge rate increases remarkably from 0.2 km(3)/kyr to 2.0 km(3)/kyr at approximately 0.2 Ma. The discharge rate is still high owing to the recent frequent activity of the Mashu caldera. The silicic magma systems of the Akan, Kutcharo, and Mashu calderas formed independently. On the other hand, the magma olAtosanupuri is associated with that of Kutcharo caldera., JAPAN ASSOC MINERALOGICAL SCIENCES
    JOURNAL OF MINERALOGICAL AND PETROLOGICAL SCIENCES, 2012年02月, [査読有り]
  • Tephrostratigraphy and petrological study of Chikurachki and Fuss volcanoes, western Paramushir Island, northern Kurile Islands: Evaluation of Holocene eruptive activity and temporal change of magma system
    Takeshi Hasegawa; Mitsuhiro Nakagawa; Mitsuhiro Yoshimoto; Yoshihiro Ishizuka; Wataru Hirose; Sho-ichi Seki; Vera Ponomareva; Rybin Alexander, A tephrostratigraphic and petrological study of the Chikurachki (1816 m)-Tatarinov-Lomonosov volcanic chain (CTL volcanic chain) and Fuss (1772 m), located at the southern part of Paramushir Island in the northern Kurile Islands, was carried out to reveal the explosive eruption history during the Holocene and the temporal change of the magma systems of these active volcanoes. Tephra successions were described at 54 sites, and more than 20 major eruptive units were identified, consisting of pumice fall, scoria fall and ash fall deposits, each of which are separated by paleosol or peat layers. The source volcano of each recognized tephra layer was confirmed by correlation with proximal deposits of each eruption center with respect to petrography and whole-rock and glass chemistry. The age of each layer was determined by radiocarbon dating and the stratigraphic relationship with the dated, widespread tephra from Kamchatka according to the thickness of paleosols bracketed between tephra layers. The Holocene activity in this region was initiated by eruptions from the Tatarinov and Lomonosov volcanoes. After the eruptions, the Fuss and Chikurachki volcanoes started their explosive activities at ca. 7.5 ka BP, soon after the deposition of widespread tephra from the Kurile Lake caldera in southern Kamchatka. Compared with Fuss located on the back-arc side, Chikurachki has frequent, repeated explosive and voluminous eruptions. Whole-rock compositions of the rocks of the CTL volcanic chain and Fuss are classified into medium-K and high-K groups, respectively. These suggest that magma systems beneath the CTL volcanic chain and Fuss differ from each other and have been independently constructed. The rocks of the Chikurachki volcano are basalt-basaltic andesite and have gradually evolved their chemical compositions; when graphed on a SiO(2)-oxide diagram, these form smooth trends from mafic to more felsic. This suggests that the magma system evolved mainly by fractional crystallization. In contrast, matrix glass chemistries for Fuss pumices are distinct for each eruption and show different K(2)O levels on a SiO(2)-K(2)O diagram. This implies that the magma system of Fuss has been frequently replaced. Both volcanoes have been active under the same subduction system. However, the Chikurachki volcano will continue eruptive activity under a stable magma system with a higher magma discharge rate, whereas Fuss may continue construction with an intermittent supply of distinct, small magma batches. (C) 2011 Elsevier Ltd and INQUA. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
    QUATERNARY INTERNATIONAL, 2011年12月, [査読有り]
  • 北海道東部,釧路地域に分布する第四系の年代:高分解能テフラ層序に基づく対比と編年
    長谷川健; 中川光弘; 伊藤順一; 山元孝広, 筆頭著者, 筆頭, The Geological Society of Japan
    地質学雑誌, 2011年12月, [査読有り]
  • 磐梯・吾妻・安達太良:活火山ランクBの三火山
    長谷川 健; 藤縄 明彦; 伊藤 太久, 筆頭著者, 筆頭, 一般社団法人 日本地質学会
    地質学雑誌, 2011年, [査読有り]
  • 北海道東部,屈斜路・摩周カルデラ噴出物の放射炭素年代値
    山元孝広; 伊藤順一; 中川光弘; 長谷川健; 岸本博志, 担当:現地調査

    査読は内部査読, National Institute of Advanced Industrial Science and Technology, Geological Survey of Japan
    地質調査研究報告, 2010年02月, [査読有り]
  • 北海道東部,根釧原野および斜里平野における約3万5千~1万2千年前のテフラ層序と後屈斜路カルデラ火山の噴火史
    長谷川健; 岸本博志; 中川光弘; 伊藤順一; 山元孝広, 筆頭著者, 筆頭, The Geological Society of Japan
    地質学雑誌, 2009年08月, [査読有り]
  • Gravity structure of Akan composite caldera, eastern Hokkaido, Japan: Application of lake water corrections
    Takeshi Hasegawa; Akihiko Yamamoto; Hiroyuki Kamiyama; Mitsuhiro Nakagawa, 筆頭著者, Akan volcano, eastern Hokkaido, Japan, is characterized by a rectangular-shaped caldera (Akan caldera: 24 kin by 13 km) with a complex history of caldera-forming eruptions during the Quaternary. A new Bouguer anomaly map of the caldera is presented on the basis of a gravity survey around Akan volcano. As part of and in addition to this survey, we applied gravimetry over the frozen caldera lake including lake water corrections. The Bouguer map shows the distribution of at least three sub-circular minima indicative of multiple depressions inside the caldera. Lake water corrections, performed by a numerical integration method using rectangular prisms, sharpen edges of the sub-circular minima. This gravity feature is consistent with geological investigations suggesting that caldera-forming eruptions of Akan volcano occurred from at least three different sources. It is concluded that Akan caldera can be described as a composite caldera with three major depressed segments., TERRA SCIENTIFIC PUBL CO
    EARTH PLANETS AND SPACE, 2009年, [査読有り]
  • 最近約1万4千年間の摩周火山のテフラ層序と噴火様式
    岸本 博志; 長谷川 健; 中川 光弘; 和田 恵冶, 責任著者, The eruptive history of Mashu volcano, located at the southeastern rim of Kutcharo caldera in eastern Hokkaido, Japan, has been divided into three stages: stratovolcano building, caldera-forming and central cone building. Tephrostratigraphy and eruption styles of the latter two stages were reinvestigated in conjunction with petrological analysis. We found new evidence of several eruptions from the volcano. These data, combined with recent 14C ages and the presence of wide-spread tephras, allow us to evaluate the temporal evolution of eruptive activity and styles of Mashu volcano during the last 14,000 years. After the formation of the stratovolcano, activity of the caldera forming stage started with plinian eruption (Ma-l) about 14cal ka. Approximately 7.5cal ka, climactic caldera-forming activity began with a phreatomagmatic eruption (Ma-j) followed by plinian falls (Ma-i~g), and a catastrophic pyroclastic flow (Ma-f) occurred resulting to the formation of the summit caldera, 7.5×5.5km in diameter. Total volume of the climactic eruption deposit is estimated to be 18.6km3. Temporal variation of pumice/lithic fragment and white (silicic)/gray (mafic) pumice ratio with eruption sequence suggest withdrawal of a zoned magma chamber with more silicic magma overlying more mafic one through the newly opened and enlarging vent. In the central cone building stage, at least eight eruptions (Ma-e, Ma-e´, Ma-d, Ma-c4~-c1 and Ma-b, in ascending order) have occurred repeatedly during the last 6,000 years. The latest eruption (Ma-b: ca. 0.9cal ka) was the largest one in this stage. Although most of the tephra layers in this stage are composed of pyroclastic fall deposits, thin pyroclastic flow deposits can also be recognized from the two eruptions (Ma-e and-d). Juvenile materials in the Mashu tephras are commonly pyroxene dacite (SiO2=64-72wt.%, K2O=0.5-0.7wt.% in whole-rock compositions). The pumice of the caldera-forming stage are nearly aphyric (1~6wt.%), whereas those of the central cone building stage are more porphyritic (13~24wt%). They can be also distinguished in SiO2-oxides diagrams. Most of Mashu tephras consist of gray fine ash layers including blocky lithic/pumice fragments and accretionary lapilli, indicative of magma-water interactions. In the case of large eruptions, such as the climactic caldera-forming eruption (Ma-j~f) and Ma-b, eruptive styles changed from the wet to dry due to increase of the magma/water ratio. The long-term magma discharge rate was 0.8 and 0.3km3 DRE/ky during the last 14,000 and 6,000 years, respectively. Mashu volcano can be interpreted as one of the most productive and active volcanoes in Japan during Holocene., 特定非営利活動法人 日本火山学会
    火山, 2009年, [査読有り]
  • 北海道東部阿寒火砕堆積物中に挟在する複数の広域火山灰層と北海道中央部に分布する太規模火砕流堆積物との対比
    長谷川 健; 石井 英一; 中川 光弘, 筆頭著者, 北海道東部の阿寒火砕堆積物(上位から, Ak1~Ak17)に挟在する6層の広域火山灰(上位から, HR-1~HR-6)と,北海道中央部の大規模火砕流について,火山ガラス組成,鉱物組み合わせおよび層序などの点から対比の検討を行った.その結果,HR-5,-6と十勝火砕流堆積物(1.3~1.46 Ma),HR-4と十勝三股火砕流堆積物(1.0 Ma),HR-2と上然別軽石流堆積物,そしてHR-1と上旭ヶ丘軽石流堆積物がそれぞれ対比された.さらに,上旭ヶ丘軽石流堆積物からは約0.51 MaのK-Ar年代を得た.以上から,北海道中央部と東部では,前期~中期更新世の80万年間にわたって大規模な火砕噴火活動が並行していたことが明らかとなった.特にAk14とこれに挟在するHR-5との間には,古土壌などが示す顕著な時間間隙が存在しないことから,この時期では北海道中~東部で同時噴火が起こっていた可能性を指摘できる., 日本地質学会
    地質學雜誌 = THE JOURNAL OF THE GEOLOGICAL SOCIETY OF JAPAN, 2008年07月15日, [査読有り]
  • 北海道北部, 大曲断層近傍の背斜成長の開始時期
    石井 英一; 安江 健一; 大平 寛人; 古澤 明; 長谷川 健; 中川 光弘, 北海道北部,大曲断層近傍の背斜成長の開始時期を知るために,同背斜軸部周辺の新第三紀珪質岩を対象にボーリングコア観察,露頭観察および室内分析(火山灰分析・FT年代測定)を行い,挟在する凝灰岩層の記載岩石学的特徴と堆積年代,珪藻質泥岩と珪質泥岩の境界面(opal-Aとopal-CTの続成境界面)の深度分布,および岩石の有効間隙率を明らかにした.凝灰岩層の対比から,2層の凝灰岩層(HT1, HT2)が背斜軸部周辺で追跡でき,HT1から約2.9 Ma,HT2から約2.2 MaのFT年代を得た.これらの凝灰岩層とHT2の最大埋没深度に基づき背斜軸部周辺の約2.9 Ma以降の堆積速度を検討すると,約2.2 MaからHT2最大埋没時(遅くとも約1.0 Ma)の間に背斜軸部の堆積速度が周囲より有意に遅くなり始めたことが示唆される.このことから,約2.2~約1.0 Maの間に大曲断層近傍の背斜成長が開始したと考えられる., 日本地質学会
    地質學雜誌 = THE JOURNAL OF THE GEOLOGICAL SOCIETY OF JAPAN, 2008年06月15日, [査読有り]
  • 北海道東部, 阿寒カルデラ周辺の前-中期更新世火砕堆積物の層序
    長谷川 健; 中川 光弘, 筆頭著者, 北海道東部,阿寒カルデラ周縁の火砕堆積物を調査し,その層序・年代を明らかにした.対比にあたっては本質物の岩石学的特徴も活用した.阿寒カルデラ起源の火砕堆積物は,古土壌などの介在によって,少なくとも40の噴火ユニットに区分できる.さらにこれらは,層序が連続し,かつ岩石学的特徴が類似する17の噴火グループにまとめられる(上位からAk1~17).Ak1~17の間には,阿寒火山以外に給源を持つ複数の火砕物が挟在する.Ak2とAk3の間には東燐の屈斜路カルデラから噴出した古梅溶結凝灰岩(0.34 Ma)が,Ak14の中には北海道中央部起源である十勝火砕流(1.3-1.46 Ma)の遠方相が堆積する.このことから,阿寒カルデラは前期更新世から活動を開始し100万年以上にわたって火砕噴火を頻発していたことが分かった.この期間,阿寒火山では,噴火グループごとに異なるマグマ系が活動していた.
    , 日本地質学会
    地質學雜誌 = THE JOURNAL OF THE GEOLOGICAL SOCIETY OF JAPAN, 2007年02月15日, [査読有り]
  • Gravity structure of the Akan Caldera and its vicinity, Eastern Hokkaido, Japan
    Takeshi Hasegawa; Akihiko Yamamoto; Hiroyuki Kamiyama; Mitsuhiro Nakagawa, 筆頭著者, 筆頭

    査読は内部査読
    Journal of the Hokkaido University, Faculty of Science, Series VII: Geophysics, 2006年12月, [査読有り]
  • Gravity anomaly and intrusive style of the tilted Tottabetsu plutonic complex, Hidaka Mountains, Northern Japan
    Hiroyuki Kamiyama; Akihiko Yamamoto; Takeshi Hasegawa; Takanori Kajiwara; Toru Mogi, 担当:現地調査・重力測定

    査読は内部査読
    Journal of the Hokkaido University, Faculty of Science, Series VII: Geophysics, 2006年12月, [査読有り]
  • Gravity and density variations of the tilted Tottabetsu plutonic complex, Hokkaido, northern Japan: implications for subsurface intrusive structure and pluton development
    H Kamiyama; A Yamamoto; T Hasegawa; T Kajiwara; T Mogi, An exposed cross section of the tilted Tottabetsu plutonic complex allows direct evaluation of its original 2-D cross-sectional shape and pretilting vertical density variations in both the pluton and the country rocks, which serves as a strong constraint in gravity modeling that complements information on the 'missing' pretilting horizontal dimension of this tilted pluton. The pluton is stratified with the uppermost thin granitic unit (similar to 1-km thick) and the underlying thick gabbro-diorite units (similar to 9-km thick) that preserve a stratigraphic record of numerous hotter replenishments in the form of alternation of originally horizontal mafic sheets and cumulate layers. Both the pluton and the country rocks show systematic density increase with pretilting crustal depth, but density contrast of the pluton with the country rocks varies between each unit. The 2-D cross-sectional shape and gravity analysis revealed that the pluton had a vertically-elongated shape with vertical side walls before tilting. The vertical side walls, together with the stack of the originally horizontal sheets and cumulate layers, suggests that the pluton grew only vertically by piston mechanism. The very thick, exposed cross section provides unequivocal evidence for development of such a pluton with this unusual shape and mass distribution, which has been inferred elsewhere only by some geophysical studies., TERRA SCIENTIFIC PUBL CO
    EARTH PLANETS AND SPACE, 2005年, [査読有り]

MISC

書籍等出版物

  • 「最新」地学事典
    地学団体研究会; 地学団体研究会最新地学事典編集委員会, 分担執筆
    平凡社, 2024年03月
    9784582115086
  • 富士山噴火に備える               
    科学; 編集部, 共著
    岩波書店, 2023年02月
    9784000063425
  • 5万分の一地質図幅および説明書「網走」               
    廣瀬 亘; 川上源太郎; 長谷川健; 林 圭一; 渡辺真人, 分担執筆
    地質調査所, 2018年
  • 釧路叢書「The Great Nature of Akan 阿寒の大自然誌」               
    長谷川 健, 分担執筆
    釧路市, 2017年
  • フィールド活用ハンドブック「阿寒の自然と文化-阿寒の魅力再発見 自然史の最新研究を学ぶ」               
    長谷川 健, 分担執筆
    釧路市, 2016年
  • 特集「日本をおそった巨大噴火」 雑誌『科学』               
    中川 光弘; 長谷川 健; 松本 亜希子, 分担執筆
    岩波書店, 2014年01月
  • Holocene: Perspectives, Environmental Dynamics and Impact Events               
    Takeshi Hasegawa, 分担執筆
    Nova Science Publishers, 2013年02月
    9781622577224
  • Arctic Circle               
    長谷川 健, 分担執筆
    財団法人北方文化振興協会, 2012年
  • 『日本地方地質誌 北海道地方』日本地質学会編               
    長谷川健; 中川光弘, 分担執筆
    朝倉書店, 2010年11月
    9784254167818

講演・口頭発表等

担当経験のある科目(授業)

  • 地質調査法               
    茨城大学
  • 岩石学実験               
    茨城大学
  • 火山学               
    茨城大学
  • 野外巡検               
    茨城大学
  • 地学実験               
    茨城大学
  • 地球惑星科学               
    茨城大学

所属学協会

  • IAVCEI (International Association of Volcanology and Chemistry of the Earth's Interior)
  • 日本鉱物科学会
  • 日本文化財科学会
  • 日本火山学会
  • 日本地球惑星科学連合
  • 日本地質学会
  • AGU (The American Geophysical Union)

共同研究・競争的資金等の研究課題

社会貢献活動

メディア報道

  •    福島県火山防災シンポジウム               
    信濃毎日新聞, 朝日新聞, 2024年08月, 新聞・雑誌
  • 【シゴトを知ろう】火山学者 編
    株式会社マイナビ, 進路のミカタ, インターネットメディア