6 0 0 0 OA 複数回の噴火で形成された箱根火山二子山溶岩ドーム
- 著者
- 笠間 友博 山下 浩之 萬年 一剛 奥野 充 中村 俊夫
- 出版者
- 一般社団法人 日本地質学会
- 雑誌
- 地質学雑誌 (ISSN:00167630)
- 巻号頁・発行日
- vol.116, no.4, pp.229-232, 2010 (Released:2010-10-13)
- 参考文献数
- 21
- 被引用文献数
- 1
The Futagoyama lava dome, one of the post-caldera central cones of Hakone volcano (Kanagawa, Japan), is though to have formed by a single eruption at 5 ka. However, in this study, we show that the dome formed over the course of at least three eruptions. We discovered a relatively old block-and-ash flow deposit (Hakone-Futagoyama Yamazaki block-and-ash flow deposit [Hk-FtY]) that originated from the Futagoyama lava dome, as indicated by its chemical composition and its age of 20,390 ± 40 yr BP. We also re-examined the source of the Shinanoya pyroclastic flow deposit, which was previously interpreted to be of Komagatake origin and was dated at 17,920 ± 320 yr BP (reference), and concluded that this deposit also originated from the Futagoyama lava dome. The recent eruptive history of Futagoyama suggests that its eruptions may have been synchronous with those of Kamiyama. In addition, the eruptive centers of Futagoyama and Kamiyama are aligned with each other along a linear trace.
5 0 0 0 OA プロト伊豆―マリアナ島弧の衝突付加テクトニクス
- 著者
- 平田 大二 山下 浩之 鈴木 和恵 平田 岳史 李 毅兵 昆 慶明
- 出版者
- 公益社団法人 東京地学協会
- 雑誌
- 地学雑誌 (ISSN:0022135X)
- 巻号頁・発行日
- vol.119, no.6, pp.1125-1160, 2010-12-25 (Released:2011-03-17)
- 参考文献数
- 142
- 被引用文献数
- 8 10 5
This paper reviews the geology, petrology, and tectonics of the Proto-Izu-Mariana arc against the Honshu arc, Japan, since 15 Ma, to formulate current topics related to the Pacific-type orogeny. Since the first pioneering work by Sugimura (1972), which placed the plate boundary on-land Japan north of the Izu peninsula collision-accretion tectonics of the Proto-Izu-Mariana arc against the Honshu arc started to be extensively investigated through multi-disciplinary methods. Aoike (1999) proposed a comprehensive scenario of five successive accretions of Proto-Izu to the present, with all bounded by top- and bottom-faults since 15 Ma. Oroclinal bending of the Honshu arc began simultaneously with the collision and indentation of the Proto-Izu arc, as is well documented by the Neogene paleomagnetic declination of sedimentary rocks in the Kanto district (Niitsuma et al., see summary, 1989). The entire Izu-Mariana arc is subducting without any accretion now under Honshu, as is well documented by seismic tomography imaging by Hasegawa et al. (see Hasegawa et al., 2010). Tanzawa Tonalite–Trondhjemite–Granodiolite (TTG) pluton intruded into the already-accreted Tanzawa Group at 4 Ma (Tani et al., 2010), resulting in a contact metamorphic aureole ranging from amphibolite through greenschist to zeolite facies at a depth of ca. 10 km, and tectonically denudated along the Kan-nawa fault to be exposed on the surface by 1.0 Ma. The Proto-Izu-Mariana arc was built on the Pre-Paleogene, presumably Cretaceous MORB crust on which boninitic and fractionated silicic lava flows accumulated since 48 Ma, which is older than the bending of the Hawaii–Emperor seamount chain at 43 Ma. Hence, we need another plate off Proto-Ogasawara arc, called North New Guinea plate (Seno, 1985), and ridge subduction underneath Ogasawara arc to initiate subduction magmatism. Both calk-alkali rock series (CA) and coeval blueschist–eclogite rocks are exposed along the inner wall of the Izu–Mariana trench. This strongly suggests that extensive tectonic erosion occurred, resulting in the coexistence of two rock units that were formed 100-150 km from each other horizontally, i.e., rocks on the volcanic front and rocks on the descending oceanic slab. Petrogenesis of juvenile crust and TTG rocks are being debate with two models: basaltic arc magma fractionation (Kawate and Arima, 1998) and delaminated mafic lower crust (Nakajima and Arima, 1998). In the latter model, a difficulty is derived from density at the Moho depth and small size of delaminated residue. Instead, extensive tectonic erosion that transports not only the upper crust but also the lower mafic crust together with parts of the descending slab could be more plausible than these two models in order to present a thinner mafic lower crust.
1 0 0 0 複数回の噴火で形成された箱根火山二子山溶岩ドーム
- 著者
- 笠間 友博 山下 浩之 萬年 一剛 奥野 充 中村 俊夫
- 出版者
- 一般社団法人 日本地質学会
- 雑誌
- 地質学雑誌 (ISSN:00167630)
- 巻号頁・発行日
- vol.116, no.4, pp.229-232, 2010
- 被引用文献数
- 1
The Futagoyama lava dome, one of the post-caldera central cones of Hakone volcano (Kanagawa, Japan), is though to have formed by a single eruption at 5 ka. However, in this study, we show that the dome formed over the course of at least three eruptions. We discovered a relatively old block-and-ash flow deposit (Hakone-Futagoyama Yamazaki block-and-ash flow deposit [Hk-FtY]) that originated from the Futagoyama lava dome, as indicated by its chemical composition and its age of 20,390 ± 40 yr BP. We also re-examined the source of the Shinanoya pyroclastic flow deposit, which was previously interpreted to be of Komagatake origin and was dated at 17,920 ± 320 yr BP (reference), and concluded that this deposit also originated from the Futagoyama lava dome. The recent eruptive history of Futagoyama suggests that its eruptions may have been synchronous with those of Kamiyama. In addition, the eruptive centers of Futagoyama and Kamiyama are aligned with each other along a linear trace.
- 著者
- 山下 浩之 平田 大二 小出 良幸
- 出版者
- 神奈川県立生命の星・地球博物館
- 雑誌
- 神奈川県立博物館研究報告 自然科学 (ISSN:04531906)
- 巻号頁・発行日
- no.34, pp.27-46, 2005-03
1 0 0 0 OA 箱根火山における地図の活用
- 著者
- 新井田 秀一 山下 浩之 笠間 友博
- 出版者
- 日本地図学会
- 雑誌
- 地図 (ISSN:00094897)
- 巻号頁・発行日
- vol.49, no.3, pp.3_28-3_37, 2011 (Released:2015-11-07)
- 参考文献数
- 27
Map is one of the most appropriate and synthetic ways of understanding the features of Hakone volcano: landform, surface formulation processes, distribution of volcanic ejecta, and also geo-historical development. Topographic map can show basic geographic information and is useful to many kinds of professional such as civil engineers, forest scientists, naturalists, and land conservationists. Nowadays, the development of remote sensing and GIS have added further valuable information to classical maps. Bird’s eye view map made by satellite image or shading image gives unique and useful views of landscape. Shadow maps, shape maps, and geologic maps are also useful, but in general they are not popular. Therefore, we have tried map-integration among bird’s eye view map and those maps of other types.
- 著者
- 森 慎一 山下 浩之 有馬 眞 藤岡 換太郎
- 出版者
- 一般社団法人 日本鉱物科学会
- 雑誌
- 岩石鉱物科学 (ISSN:1345630X)
- 巻号頁・発行日
- vol.41, no.3, pp.67-86, 2012 (Released:2012-06-28)
- 参考文献数
- 185
- 被引用文献数
- 2 3
We determined K-Ar ages of the late Miocene to Pliocene andesitic to basaltic dykes and lavas distributed in the Tanzawa-Oiso area in the southern Fossa Magna region, central Japan. Our data indicate two distinct periods of volcanic activity in this region; one took place during the middle Miocene (about 15 Ma) and another during the late Miocene to Pliocene (7.5-4.2 Ma). Combined the present results with the age data reported previously from volcanic rocks in the southern Fossa Magna region, the present study suggests that the volcanic front in this region during 8 to 4 Ma was located at about 40 km east of the present-day volcanic front. The volcanic front began to migrate westward to the present-day location at about 4 Ma. The westward migration of volcanic front was probably associated with an abrupt change of lateral motion of the Philippine Sea Plate from north- northwestward to northwestward occurred between 4 and 2 Ma.
1 0 0 0 D247 野外学習指導法の体系化に関する研究
- 著者
- 下野 洋 市川 智史 梅埜 国夫 小椋 郁夫 恩藤 知典 河原 富夫 小島 繁男 小林 道正 五島 政一 佐藤 俊一 猿田 祐嗣 下畑 五夫 浜中 正男 藤田 郁男 松田 義章 三宅 征夫 山下 浩之 山田 正昭 渡辺 享
- 出版者
- 一般社団法人 日本科学教育学会
- 雑誌
- 日本科学教育学会年会論文集
- 巻号頁・発行日
- vol.19, pp.315-316, 1995
理科の野外学習指導法の体系化を図るために、野外学習の有効性、必要性、児童・生徒の環境認識の実態、野外学習の目標、カリキュラム上の位置付け、野外学習の指導の型、観察対象の類型化、野外学習の指導法などについての検討を行った中間報告である。
1 0 0 0 OA 箱根火山芦ノ湖の湖底における箱根町断層地形
- 著者
- 平田 大二 山下 浩之 坂本 泉 小田原 啓 滝野 義幸 鬼頭 毅 藤巻 三樹雄 萬年 一剛 新井田 秀一 笠間 友博 齊藤 靖二
- 出版者
- 公益社団法人 東京地学協会
- 雑誌
- 地学雑誌 (ISSN:0022135X)
- 巻号頁・発行日
- vol.119, no.5, pp.911-916, 2010-10-25 (Released:2011-01-21)
- 参考文献数
- 12
The bottom topography of lake Ashi-no-ko, in the Hakone volcano caldera, was examined using the SeaBat8101 narrow multi-beam sonar system. The purpose of micro-topographical observations of the lake bottom is to understand the tectonic relations between the historical formation-process of the caldera and the strike-slip motion in the Tanna-Hirayama active fault system. At the southeastern part of the lake, west of the Dougashima, undulations at the bottom such as swells, hollows, and stairs extending in the northwest-southeast direction, were observed. These bottom-forms show a northern extension of the Hakonemachi active fault, running along the east side of lake Ashi-no-ko. They may correspond to one of the north spray faults of the Kita-Izu active fault system, which is the source of the A.D.1930 Kita-Izu earthquake, and to motions of the western margin of the Manazuru micro-plate, in relation to caldera formation as a strike-slip basin.
- 著者
- 平田 大二 山下 浩之 谷口 英嗣 菅 香世子 西川 正 青池 寛 有馬 眞 鈴井 正和
- 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
- 巻号頁・発行日
- vol.1996, no.2, 1996-11-05
1 0 0 0 OA 自然と歴史の融合プログラム開発と新しい博物館教育-箱根火山と築城を例に-
1 0 0 0 野外学習の学校教育における位置づけ
1 0 0 0 OA 地球システム相互作用の理解に基づく地球史学習プログラムの構築
46億年にわたる地球史・生命史に関する情報を収集し、地球史・生命史イベントと地球システムの相互作用を理解するための総合年表の作成を進めた。当館が所蔵する標本や画像など各種資料のデータベースを再構築するとともに、それを補完する標本と資料の収集を進めた。それらを活用した地球史学習プログラムとして、常設展示の展示標本と解説資料を活用した、地球の歴史の中でおきた現象と地球システムについて理解できる双方向形式の連続講座を実施した。参加者が地球史・生命史について理解を深め、現在および未来の地球について考えることができ、地球科学リテラシーの涵養を図ることが出来る環境を提供できた。
1 0 0 0 OA 自然災害教育プログラムの開発による新しい博物館機能の開拓
1 0 0 0 自然を理解するための人と博物館のネットワークの構築
1.自然史リテラシーの育成を目指した学習プログラムの開発と実践自然を総合的、能動的にとらえ、自然に接する能力や態度をもつことができるような自然史リテラシー育成の取り組みを行うとともに,市民の自然に対する知的好奇心と知的ニーズに応えるため,「誰もが,いつでも,どこでも,いくらでも」利用できる学習システムの運用と実践を行った.さらに地域の自然と実物標本からなる各種データベースの構築し、ネットワークを活用した自然を理解するための学習プログラムを展開した。2.インターネットを活用した人と博物館のネットワークの構築遠隔地の博物館同士、あるいは博物館と利用者とが相互交流できるインターネットを活用した双方向型ネットワーク・システムの構築し、実践と評価を行った。また、小中学校における授業や課外活動での連携、博物館活動におけるボランティアや友の会との連携などの活動を展開し、児童生徒から社会人、研究者まで多様な階層を交えたネットワークの構築を試みた。3.データベースの拡充すでに公開しているデータベース「地球のからくり」、「神奈川の大地」、「地球地学紀行」、「人と大地と」に加えて、神奈川県および周辺地域を対象とした地球科学分野のデータベース(DB)「神奈川の地球誌」の構築を進めた。さらに火山灰DBと神奈川の川DBの構築、地球科学文献DB、丹沢山地の地形・地質DB、航空写真DB、の補完、愛媛県西予市城川地質館と周辺地域を対象とした地形地質DBの補完を行った。