著者

筒井 智樹 井口 正人 為栗 健 上田 義浩 大島 弘光 植木 貞人 大湊 隆雄 及川 純 市原 美恵 野上 健治 中道 治久 大倉 敬宏 清水 洋 宮町 宏樹 八木原 寛 前川 徳光 堀川 信一郎 吉川 慎 園田 忠臣 平野 舟一郎 末峯 宏一 林 幹太 加藤 幸司 長尾 潤 池亀 孝光 松末 伸一 五藤 大仁 河野 太亮 簗田 高広 田中 窓香 渡辺 竜一 長岡 優 前原 祐樹 吉田 沙由美 小林 由実 栢橋 志郎

出版者

京都大学防災研究所

雑誌

京都大学防災研究所年報. B = Disaster Prevention Research Institute Annuals. B (ISSN:0386412X)

巻号頁・発行日

vol.53, no.B, pp.241-260, 2010-06-01

著者

栁澤 宏彰 及川 輝樹 川口 亮平 木村 一洋 伊藤 順一 越田 弘一 加藤 幸司 安藤 忍 池田 啓二 宇都宮 真吾 坂東 あいこ 奥山 哲 鎌田 林太郎 兒玉 篤郎 小森 次郎 奈良間 千之

出版者

特定非営利活動法人 日本火山学会

雑誌

火山 (ISSN:04534360)

巻号頁・発行日

vol.67, no.3, pp.295-317, 2022-09-30 (Released:2022-10-27)

参考文献数

73

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The 2016 eruptions of Niigata-Yakeyama volcano in central Japan consisted of several small eruptions that were accompanied by syneruptive-spouted type lahars. We have reviewed the sequence of the 2016 activity and modeled the eruptive processes based on observations of various volcanic phenomena, including ash fall and lahars, plumes, earthquakes and crustal deformation, and analysis of eruptive products. Eruptions of Niigata-Yakeyama volcano after the 20th century can be categorized into two types; 1) VEI=0-1 eruptions during which ash fall covered only the summit area and no ballistic blocks were ejected (e.g., 1997-1998 event) and 2) VEI=1-2 eruptions during which ash fall reached the foot of the mountain with ejected blocks (e.g., 1974 event). We also discuss the characteristics of the 2016 activity by comparing the sequence with those of other events of Niigata-Yakeyama volcano: the 1974 and 1997-1998 eruption events and the 2000-2001 intensified fumarolic event. The 2016 eruptions of Niigata-Yakeyama volcano are divided into the following six stages. Stage I was characterized by the onset of intensified steam plume emission activity (≥200 m). Stage II was characterized by the onset of crustal deformation, slight increase of high frequency earthquakes (approx.>3.3 Hz) and further activation of steam plume emission activity (≥500 m). The crustal deformation observed commenced at the beginning of Stage II and lasted until the end of Stage V. The total inflated volume was estimated to be approximately 7.2×106 m3. Several very small eruptions that provided only a small amount of ash to the summit area also occurred. Stage III was characterized by a rapid increase of high frequency earthquakes accompanied by tilt change, and the onset of low frequency earthquakes (approx.<3.3 Hz). A small eruption was accompanied by a syneruptive-spouted type lahar at this time. Stage IV was characterized by the occurrence of several small syneruptive-spouted type lahars. The occurrence of high and low frequency earthquakes continued, but with decreasing abundance. Stage V was characterized by the highest altitude of steam plume emission (≥1,200 m), while no ash emission nor syneruptive-spouted type lahars were observed. Stage VI was characterized by a gradual decrease in steam plume emission and earthquake activity. The aerial photographs indicate the ash fall distribution, and the maximum scale of the 2016 eruption, which is estimated to be VEI=1. The assemblage of altered minerals indicates that the volcanic ash originated from volcanic conduits affected by a high-sulfidation epithermal system and no magmatic components were detected. Judging from the depth of the crustal deformation source of magmatic eruptions at other volcanoes, the estimated source of crustal deformation during the 2016 eruption is considered to have been caused by a volume change of the magma chamber. The sequence of the 2016 event can be interpreted as follows: 1) magma supply to the magma chamber, 2) increase in seismicity and fumarolic activity triggered by volcanic fluid released from the new magma, 3) destruction of volcanic conduit by increased fumarolic activity and emission of volcanic ash, and 4) occurrence of syneruptive-spouted type lahars by the “airlift pump” effect. At Niigata-Yakeyama volcano, such small eruptions and fumarolic events have been frequently observed for the last 40 years. We thus consider that the accumulation of magma has progressed beneath the volcano, which is a potential preparatory process for a future magmatic eruption.

著者

藤原 善明 飯島 聖 坂井 孝行 加藤 幸司 中村 政道 内藤 宏人 山里 平 中禮 正明 平松 秀行 上田 義浩

出版者

特定非営利活動法人 日本火山学会

雑誌

日本火山学会講演予稿集 (ISSN:24335320)

巻号頁・発行日

vol.2004, 2004

著者

加藤 幸司

出版者

慶應義塾大学体育研究所

雑誌

体育研究所紀要 (ISSN:02866951)

巻号頁・発行日

vol.60, no.1, pp.1-6, 2021-01

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The purpose of this study was to investigate the temporal and notational structures of mixed doubles and women's doubles games in badminton doubles events and obtain basic information for coaches and players in order to set up specific badminton training drills. Eleven matches of each event (n= 22) were selected from the top categories of BWF World Tour tournaments held from 2018 to 2019 and analyzed. Total rally time (XD:637.9 ± 106.7 s vs . WD : 1135.1 ± 523.7 s ; P< 0.05), rally time (XD: 8.2 ± 1.4 s vs . WD : 13.5 ± 4.2 s ; P< 0.05), percentage of time played (XD : 26.1 ± 3.1 % vs . WD : 35.3 ± 6.3%;P< 0.05), work density (XD : 0.35 ± 0.05 vs . WD:0.55 ± 0.16;P< 0.05), total shots (XD : 899.4 ± 139.8 vs . WD : 1350.8 ± 578.2;P< 0.05), and shots per rally (XD:11.4 ± 1.7 vs . WD:16.1 ± 4.4;P< 0.05) were significantly higher in the women's doubles event than in the mixed doubles event. Shot frequency showed a significantly lower value in the women's doubles event (XD:1.41 ± 0.04 vs . WD : 1.21 ± 0.06 ; P< 0.05). Tempo (total rally time / total shots) was significantly shorter in the mixed doubles than in the women's doubles (XD : 0.76 ± 0.02 s vs . WD : 0.83 ± 0.04 s ; P< 0.05). In conclusion, comparing the mixed doubles and the women's doubles, we found that the temporal and notational structures of both events were different. The significant differences in the data observed between the events may help coaches and players effectively and efficiently manage training and competition preparation in line with current badminton events characteristics.

著者

宮町 宏樹 泊 知里 八木原 寛 井口 正人 為栗 健 山本 圭吾 大倉 敬宏 安藤 隆志 尾西 恭亮 清水 洋 山下 裕亮 中道 治久 山脇 輝夫 及川 純 植木 貞人 筒井 智樹 森 済 西田 誠 平松 秀行 小枝 智幸 増田 与志郎 加藤 幸司 畠山 謙吾 小林 哲夫

出版者

特定非営利活動法人日本火山学会

雑誌

火山 (ISSN:04534360)

巻号頁・発行日

vol.58, no.1, pp.227-237, 2013-03-29

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2008年に実施された屈折法地震探査によって得られたP波初動走時により,姶良カルデラおよび桜島火山の深さ3kmまでの速度構造を推定した.本研究地域の基盤層である四万十層群は4.6-5.0km/sのP波速度を持ち,姶良カルデラの中央部に向け傾斜している.姶良カルデラの中央部には,4.2-4.4km/sの低速度域が深さ1.5-3kmに存在している.そして,この低速度域はカルデラ下に存在する深部マグマ溜まりからのマグマ供給系が活発であることを示唆している.また,基盤層は鹿児島地溝帯の北西域の境界に沿って深さ1kmから2.5kmに急激に落ち込んでいることがわかった.桜島火山の速度構造は3.6-3.7km/sの領域が存在することで特徴づけられる.桜島火山の山頂直下で発生している火山性地震の震源域と速度構造の比較から,地下構造が種々の火山性地震の震源域の広がりに強い影響を与えていることを示した.