著者
南 裕介 伊藤 順一 草野 有紀 及川 輝樹 大場 司
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.68, no.2, pp.39-57, 2023-06-30 (Released:2023-07-27)
参考文献数
39

Akita-Yakeyama Volcano is an active stratovolcano located on Northeast Honshu island, Japan. Recent eruptive activity has occurred on the flank of the volcano in May 1997 and in the summit crater (Karanuma vent) in August 1997. These events indicate that Akita-Yakeyama Volcano has a high potential for future eruptions. In order to better understand the hazards posed by Akita-Yakeyama Volcano, this study focused on the modern explosive activity of Akita-Yakeyama during the last 6000 years. The authors conducted field observations and excavation surveys at outcrops, whole-rock chemical analysis, volcanic glass chemical analysis, and radiocarbon dating for intercalated paleosol layers. As a result, at least nine layers of pyroclastic fall deposits derived from Akita-Yakeyama during the last 6000 years were recognized, ranging from Volcanic Explosivity Index (VEI) levels of 1 to 2. In chronological order, the major pyroclastic fall deposits consist of AKY8 (45th to 47th century BC), AKY7 (10th to 29th century BC), AKY6 (2nd to 8th century BC), AKY5 (1st century BC to 2nd century AD), AKY4 (5th to 9th century AD), AKY3 (1678 AD), AKY2 (1892 AD), AKY1 (1951 AD) and 1997 eruption ejecta. The decreasing proportion of juvenile materials in eruptive deposits over the last 6000 years is consistent with a reduced magma contribution. It indicates that the development of the hydrothermal system is likely to play an important role in future eruption scenarios for Akita-Yakeyama Volcano.
著者
及川 輝樹 筒井 正明 大學 康宏 伊藤 順一
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.57, no.4, pp.199-218, 2012-12-28 (Released:2017-03-20)
参考文献数
65

Shinmoedake (Kyushu, Japan), which is one of the Kirishima Volcanoes, experienced several small eruptions in 2010, finally culminating in a sub-plinian eruption on January 26-27, 2011. After this sub-plinian phase, the eruption style shifts to the phase of vulcanian eruption or ash emission. This volcanic activity is still occurring. We here summarize the eruption history of Shinmoedake during the Edo period on the basis of historical records. The eruptions of Shinmoedake during the Edo period occurred in AD 1716-1717 (Kyoho eruption) and AD 1822 (the 4th year of Bunsei eruption). The Kyoho eruption, which was a large-scale (total amount of tephra: 2×1011 kg) eruption, is divided into the following seven stages. Stage 1 (Apr. 10, 1716 to May 7, 1716): small eruptions occurred over two months; Stage 2 (Sep. 26, 1716): falling ash first observed at the foot of Shinmoedake; Stage 3 (Nov. 9 to 10, 1716): the first large eruption was observed, with pumice falling over a wide area; Stage 4 (Dec. 4 to 6, 1716): small eruptions; Stage 5 (Feb. 9 to 20, 1717): the second pumice fall eruption, with an intermittent ash fall eruption thereafter; Stage 6 (Mar. 3, Mar. 8, Mar 13, Apr. 8, 1717): ash fall eruptions; Stage 7 (Sep. 9, 1717): the last ash fall eruption. These eruptions, which continued intermittently over 17 months, were characterized by multiple repetitions of a large eruption. Based on the results of a comparison between the Kyoho eruption and the 2011 eruption, the eruptions from March 30, 2010 to January 26, 2011, were similar to Stages 1 to 3 of the Kyoho eruption; the eruptions after January 26, 2011, were similar to Stages 5 to 6 of the Kyoho eruption. In addition, the relatively large eruption events of Stages 3 and 5 of the Kyoho eruption and the January 26-27, 2011, eruption began without any noticeable precursors. The eruption in the 4th year of Bunsei (AD 1822) was a small eruption that lasted less than a day. The recent eruption sequences, which were also similar to the Edo period eruptions, are divided into a small-scale eruption (the 1959 eruption) and a large-scale eruption (the 2011 eruption). The eruption duration time of the small-scale (total amount of tephra: < 1010 kg) eruption was less than a day. The eruption duration time of the large-scale (total amount of tephra: > 1010 kg) eruption could be a few months or years. Both eruption sequences began with a small eruption. A large-scale eruption can occur a few months after the start of the eruption sequence. This is an important turning point in the eruption sequence of Shinmoedake.
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

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
長谷川 健 中川 光弘 伊藤 順一 山元 孝広
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.117, no.12, pp.686-699, 2011-12-15 (Released:2012-03-26)
参考文献数
30
被引用文献数
7 6

テフラを用いて北海道東部の釧路地域に分布する第四系の編年を試みた.釧路地域の海成層(上位から,大楽毛層,釧路層)の各模式地において複数のテフラを記載・採取し,火山ガラスの主成分化学組成などの岩石学的特徴や層位関係から,阿寒・屈斜路火山地域のテフラと対比を行った(阿寒および屈斜路テフラはそれぞれ上位から,Ak1~17およびKpI~VIII).大楽毛層の上位にはKpVIが見いだされ,また大楽毛層上部と下部に挟まる2層の火山灰層は,それぞれAk5および給源不明の広域テフラ(LowK-1)に対比される.一方,釧路層中に含まれる軽石礫・溶結凝灰岩岩塊は,すべてAk13~Ak17由来である.以上の対比結果と既報のテフラ年代から,大楽毛層の堆積は,少なくとも,0.8 Maに開始し0.1 Maより前に終了したと推測できる.釧路層の堆積時期は,1.5 Ma以降,1.0 Maより前と考えられる.
著者
北村 義治 伊藤 順一
出版者
Japan Society of Corrosion Engineering
雑誌
防蝕技術 (ISSN:00109355)
巻号頁・発行日
vol.13, no.6, pp.256-261, 1964-06-15 (Released:2009-11-25)
参考文献数
3

The corrosion of austenitic stainless steels and titanium in the aqueous solutions of several amino acid and their salts was investigated. The total immersion tests, the cell voltage-current curve method and the potentiostatic polarization curve method were adopted.The following experimental results were obtained: The aqueous solutions of acidic amino acids such as glutamic acid or homocysteic acid were comparatively corrosive, while neutral and basic amino acids scarcely; the corrosive behaviors of acid and basic salts of various amino acids bore some resemblance to those of acids and bases which were estimated to be freed from the salts.It is suggested that amino acids, which form salts with acids or bases, might have some neutralizing action on them, resulting in reduction in the corrosive effects of these salt solutions.
著者
伊藤 順一郎 福井 里江 坂田 増弘 山口 創生 種田 綾乃 相川 章子 伊佐 猛 市川 亮 伊藤 明美 大島 真弓 岡本 和子 黒木 紀子 坂本 麻依 佐竹 直子 佐藤 由美子 澤田 優美子 関根 理絵 富沢 明美 友保 快児 二宮 史織 久永 文恵 藤田 英親 松長 麻美 松谷 光太郎 村木 美香
出版者
国立研究開発法人国立精神・神経医療研究センター
雑誌
基盤研究(B)
巻号頁・発行日
2013-04-01

本研究の目的は、共同意志決定 (SDM)を促進するツール(SHARE)を用いた包括的なSDMシステムの構築とその効果検証であった。SHAREは利用者のリカバリーゴール(希望する生活の実現に向けた目標)や自身の精神的健康にとって大切なこと、自身の状態を適切に医師に伝えることに焦点を当てたPCソフトウェアである。利用者は診察前にピアスタッフのサポートを受けながら自身の情報をSHAREに入力した。医師はSHAREの情報をもとに診察を進め、診察の最後にSDMを実施する。このSDMシステムは、臨床的なアウトカムに影響を及ぼすことはなかったが、患者と医師のコミュニケーションや関係性の向上に効果を示した。
著者
小宮山 碧 伊藤 順一
出版者
地域農林経済学会
雑誌
農林業問題研究 (ISSN:03888525)
巻号頁・発行日
vol.53, no.2, pp.72-83, 2017-06-25 (Released:2017-06-30)
参考文献数
44
被引用文献数
6

The Japanese government introduced the Farmland, Water and Environmental Conservation Improvement Scheme (CIS) in 2007, with the aim of promoting collective stewardship of common pool resources (CPRs) and enhancing agricultural multi-functionality. In order for rural communities to participate in this scheme, they have to meet requirements and sign a contract with the government outlining the scope of collective action for maintaining CPRs. In this paper, we measure the treatment effect of the CIS using propensity score matching methods. Some framed field experiments in the previous literature show that extrinsic motivations such as payments or punishments for participants may not enhance collective stewardship because exter­nal intervention crowds out or undermines partici­pants’ intrinsic motivation, based on social norms and reciprocity, to cooperate. Our empirical study conducted in Shiga Prefecture, however, reveals that there is a causal effect of CIS participation for increasing collective action, suggesting that the CIS is instrumental in conserving farmland, agricultural canal, pond, and irrigation facilities. Another important finding is that pre-existing social capital fostered by community members is positively correlated with their participation in the CIS.
著者
中野 俊 伊藤 順一
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.43, no.3, pp.123-126, 1998-06-10 (Released:2017-03-20)
被引用文献数
1
著者
谷口 宏充 伊藤 順一
出版者
大阪府教育センター
雑誌
一般研究(C)
巻号頁・発行日
1994

本研究では火山噴火によって発生する爆風過剰圧などの物理量を計測し、同時に、付随する火山災害・噴出物の分布を調査し、両者の定量的な関連づけと爆発エネルギー量の決定を行おうとするものである。爆発的な噴火現象によって発生する火山災害や地質学的諸現象の分布は、爆発エネルギー量によって束縛されていると考える。もしこの考えが正しいなら、私たちは爆発エネルギーという只一個のパラメーターを定めることによって、他の全ての災害・地質現象の広がりや強度は数値シミュレションによって求めることができることになる。このことを実証するために、実際の火山噴火における爆発エネルギー計測方法の開発、実施、地質調査そして文献調査にもとづく災害・地質の諸現象と爆発エネルギー量との関連づけを試みる。1.爆発に伴う火砕流の最大到達距離は爆発エネルギー量によって規制されている。2.火口の直径は爆発エネルギー量の1/3乗に比例し、核爆発やTNT爆発などと同一の実験式によって記述される。3.マグマ噴火における熱エネルギーの爆発エネルギーへの変換効率は0.01〜0.4%、マグマ水蒸気爆発の場合には0.4〜7%程度であり、両者の間に明瞭な差がみられた。4.従って、火口直下に蓄積されている熱量や地下の帯水層に関する情報が地磁気学的な手法などによって与えられるなら、可能性のある最大爆発エネルギー量は評価され、数値シミュレションなどによって、火山爆発に伴う災害や噴出物の分布は予測できることになる。また過去の噴出物の地質学的調査を行うことによって、災害や噴出物分布についての統計的な予測をすることが可能になるかも知れない。5.阿蘇火山における1994年9月〜1995年2月までの計測結果によれば、各計測期間内における最大爆発エネルギー量は5×10^<15>erg程度であった。
著者
宇都 浩三 風早 康平 斎藤 元治 伊藤 順一 高田 亮 川辺 禎久 星住 英夫 山元 孝広 宮城 磯治 東宮 昭彦 佐藤 久夫 濱崎 聡志 篠原 宏志
出版者
学術雑誌目次速報データベース由来
雑誌
地學雜誌 (ISSN:0022135X)
巻号頁・発行日
vol.110, no.2, pp.257-270, 2001
被引用文献数
7 13

To understand the eruptive mechanism of the 2000 Miyakejima volcanic activity, we conducted intensive geological, petrographic, and mineralogical studies on the pyroclastics of the August 18 eruption. Volcanic ashes, which were rich in accretionary lapilli, covered most of the islands. Cauliflower-shaped bombs and lapilli were ejected along with accidental lava blocks. Black-colored angular scoriaceous particles with abundant vesicles 10 -100 μm in diameter are found among ashes, comprising about 40 wt. % of total constituents. These bombs, lapilli, and black ashes have identical bulk chemical compositions and constituent mineral compositions, suggesting a common origin. Existence of oxidized ashes and accretionary lapilli attached to a large flattened bomb and chemicallyreacted anhydrite particles trapped in the voids of bombs suggest that bombs were still hot and ductile when they were emplaced on the ground. We, therefore, conclude that the August 18 eruption was a phreatomagmatic eruption and cauliflower-shaped bombs and black ashes were essential magmatic materials. Significant SO<SUB>2</SUB> emissions from the volcano after August 18 also suggest convective upwelling of magmas to a shallower level beneath the volcanic edifice. We propose a magma-ascending model in which vesiculating magmas continuously ascend through the wall of subsided piston-like blocks.
著者
塚田 和美 伊藤 順一郎 大島 巌 鈴木 丈
出版者
千葉大学
雑誌
千葉医学雑誌 (ISSN:03035476)
巻号頁・発行日
vol.76, no.2, pp.67-73, 2000-04-01

心理教育が精神分裂病者の家族の感情表出(EE)を低下させ,再発を予防することが,欧米各国で報告されている。我が国の現状に即した心理教育が,同様の効果を持つかどうかを検証することは有意義だと思われる。そこで国府台病院に入院した85例の精神分裂病者とその家族を無作為に介入群と対照群に振り分け,心理教育の効果を検定した。すべての重要な家族員は入院直後,退院直後及び退院9ヶ月後にEEを測定され,介入群の家族は毎月1回,計10回の心理教育を受けた。その結果,介入群の退院後9ヶ月までの再発率は,対照群に比して有意に低下した。また,再発しやすいハイリスクグループである高EEのみの検定でも,同様の結果となった。一方,EEの下位尺度である批判的言辞(CCs)と情緒的巻き込まれすぎ(EOI)については,高CCsが両群とも時間の経過とともに有意に低下したにも関わらず,高EOIは介入を受けなければ低下しないことが明らかになった。これにより,国府台モデルの心理教育はEEの低下と再発予防に有効であることが証明された。