Search Results 1-8 of 8

  • Reconstruction of the 2014 eruption sequence of Ontake Volcano from recorded images and interviews

    Oikawa Teruki , Yoshimoto Mitsuhiro , Nakada Setsuya , Maeno Fukashi , Komori Jiro , Shimano Taketo , Takeshita Yoshihiro , Ishizuka Yoshihiro , Ishimine Yasuhiro

    … Phase 1: The eruption started with dry pyroclastic density currents (PDCs) caused by ash column collapse. … Phase 2: When the outflow of PDCs stopped, the altitude of the eruption column increased; …

    Earth, Planets and Space 68(79), 2016-05-14

    IR 

  • The pyroclastic density currents generated by the September 27, 2014 phreatic eruption of Ontake Volcano, Japan.  [in Japanese]

    Yamamoto Takahiro

    … 2) The eruption column collapse height of the pyroclastic density currents did not exceed 300 m above the vents. … this suggests that the density currents possessed sufficient heat for the ash cloud to have risen due to its buoyancy. … The Heim coefficient for the energy cone slope for the density currents is 0.45 to 0.55, when the column collapse height is 200 m. …

    BULLETIN OF THE GEOLOGICAL SURVEY OF JAPAN 65(9-10), 117-127, 2014

    J-STAGE 

  • Eruptive Sequence and Characteristics of the Irosin Ignimbrite, Southern Luzon, Philippines  [in Japanese]

    KOBAYASHI Tetsuo , Ma. Hannah T. MIRABUENO , Ma. Antonia V. BORNAS , TORII Masayuki , Eduardo P. LAGUERTA , Arturo S. DAAG , Ericson B. BARISO , NAKAMURA Toshio , OKUNO Mitsuru

    … The eruption consisted of two distinctive events, namely a precursory eruption and a large-scale caldera-forming eruption.<br> During the precursory eruption, fine ash was ejected, and a small lava dome, Malobago, was extruded on the southeastern slopes of the present caldera outline. … Partial collapse of the plinian column repeatedly occurred during the early stage of the plinian phase. …

    Journal of Geography (Chigaku Zasshi) 123(1), 123-132, 2014

    J-STAGE 

  • Response of Kanto Loam to Nitrate Pollution of Subsoil  [in Japanese]

    NAKAYAMA Chieko , TANAKA Yoshinori

    … The volcanic ash soils in Japan are known as being resistant to acidification. … However it is not clear how volcanic ash soils are affected by acid rain and fertilizer.<BR>This study examines the response of Kanto loam to pollution of subsurface layers by nitrate. … Chemical properties of Kanto loam soil samples were assessed by exchangeable acidity and soil column tests. …

    Journal of the Japan Society of Engineering Geology 47(6), 337-345, 2007-02-10

    J-STAGE  References (29)

  • Textural Variety in the Eruptive Products of Vulcanian Eruptions between 1108 A.D. and 2004 A.D. on Asama-Maekake Volcano(<Special Section>The 2004 Eruption of Asama Volcano(2))  [in Japanese]

    YASUI Maya , TAKAHASHI Masaki , SAKAGAMI Masayuki , Research Group on the Asama 2004 Eruption at Nihon University

    Ash fall deposits composed mainly of lithic fragments are often recognized in the eruptive products of Asama-Maekake Volcano. … A comparative study was made on microscopic textures of coarse-grained particles of 1 to 2mm in diameter from thirteen ash-fall deposits. … Average composition of the ash particles from Vulcanian eruptions after the 1783 eruption was also investigated using the cumulative ash-soil mixtures. …

    BULLETIN OF THE VOLCANOLOGICAL SOCIETY OF JAPAN 50(6), 501-517, 2005

    J-STAGE  References (20) Cited by (2)

  • Chronology of the Miyakejima 2000 Eruption : Characteristics of Summit Collapsed Crater and Eruption Products

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

    … Eruptives are enriched with hydrothermally altered materials such as smectite and kaolinite.<BR>The manner of the first collapse suggests the existence of a large open space under the summit just before the subsidence. … Successive formation of open spaces at deeper levels is likely to have caused the continuous collapse of the summit area. … The hydrothermal system was broken by the largest eruption on August 18, and the eruption column rose about 15 km above the summit. …

    Journal of Geography (Chigaku Zasshi) 110(2), 168-180, 2001-04-25

    J-STAGE  References (17) Cited by (36)

  • Plio-Pleistocene volcaniclastic formation in the Takayama Basin, Gifu prefecture:Stratigraphy and Petrography  [in Japanese]

    Nagahashi Yoshitaka

    … They are divided into the Matsubara Gravel Bed, Matsumoto Gravel Bed, Ogaya Formation, Nyukawa Pyroclastic Flow Deposit, Miyamae Formation, Naberidani Ash Fall Deposit, Chayano Tuff I・II, Ebisutoge Pyroclastic Deposits, Kiriyama Gravel Bed, Uwano Mudflow Deposit, Enako Gravel Bed, Kamitakara Pyroclastic Flow Deposit, and Yamaguchi Gravel Bed in ascending order. …

    Earth Science (Chikyu Kagaku) 49(2), 109-124, 1995

    J-STAGE  References (20) Cited by (4)

  • Large-scale Pyroclastic Flows and Their Source Calderas : A Review  [in Japanese]

    UI Tadahide , SUZUKI-KAMATA Keiko

    … Ground surge, ground layer, fines-depleted ignimbrite and co-ignimbrite ash fall are defined based on grain size analysis. … Gravitational column collapse model is proposed. …

    SECOND SERIES BULLETIN OF THE VOLCANOLOGICAL SOCIETY OF JAPAN 30(TOKUBE), S221-S235, 1986

    J-STAGE 

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