著者

金子 克哉 鎌田 浩毅 小屋口 剛博

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.1999, 1999

著者

鎌田 浩毅

出版者

一般社団法人 日本地質学会

雑誌

日本地質学会学術大会講演要旨 (ISSN:13483935)

巻号頁・発行日

vol.1990, 1990

著者

鎌田 浩毅 三村 弘二

出版者

特定非営利活動法人 日本火山学会

雑誌

火山.第2集 (ISSN:04534360)

巻号頁・発行日

vol.26, no.4, pp.281-292, 1981

被引用文献数

2

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Kuju Volcano (1, 786m high) consists of dacitic lava domes and the associated non-welded pyroclastic flow deposits, Handa pyroclastic flow deposits, covering 60 km² area (Fig.2). The original vents of the pyroclastic flow deposits, whose age is estimated to be 0.04 Ma, have not been located. The volume is about 2km³. They contain pumice and accessory lithic fragments and very seldom show welding. At the upper and the basal parts of one flow unit, imbrications of pumice and lithic fragments are well developed with 10°-20°dip against the flow unit boundary (Figs. 4, 5). This dip (Table 1) is apparently not as steep as that of the other pyroclastic flow deposits. Imbrications are clearly observed at 6-12km from the center of the lava domes, while the distribution of the pyroclastic flow deposits covers 4-13km from the center (Fig. 7). The pyroclastic flows ran down 1000m in a vertical distance. The method of determining the flow direction by imbrication is very simple as shown in Fig. 6. Imbrication is most visible from the direction (a) perpendicular to the flow direction on the surface of each outcrop. The flow direction (f) is determined by the bisector (f') of the error angle 2θ formed by the two directions (b, c), between which imbrication is not observed. Data are classified into 3 ranks by the error angle θ as shown in Table 1. The flow directions at 52 outcrops (Table 2) are shown by classified arrows in Fig. 7. The estimated flow-direction patterns are largely divided into the north-flank flows and the south-flank flows (Fig. 7). The north-flank pyroclastic flow deposits flowed along the 2 km-wide major valley on ca 2°slope shown in K-L profile in Figs. 8, 10. Then it diverged to the west at the outlet of the valley, and finally collected in a small basin in the west. Such flow directions suggest that the flow was not derived from the adjacent domes D, E, F in Fig. 7. On the south flank, a fan-shaped pattern of the flow direction is generally observed. But the flows toward Aso volcano are sharply separated into two flows at the boundary between Kuju and Aso ("col" in Figs 7, 9). This is because the flow had not enough power to rush up the very gentle slope of Aso volcano. The evidence shows that the southward flow gradually bent 120°, and it rapidly went down eastward on the south flank. At Takenohata (n. in Fig. 7) this eastward flow crossed the southward flow. At this cross point, lower outcrops show eastward flow (A-B profile in Fig. 8), and higher ones show southward flow (C-D profile) as shown in Fig. 11. This means that after the eastward flow filled the old valley extending in east-west direction, the later pyroclastics flowed southward over the older deposits forming a fan-shaped deposit. Data clearly suggest that the vent for the pyroclastics is located within the circle around A, B, C lava domes, and not in the other domes. The flow directions indicated by imbrications agree with the distribution of the pyroclastic flow deposits. Pyroclastic flows follow the previous topographic relief such as valley, fan, and col. Kuju Volcano may not have emitted the flooded sheet-flows in all directions, but have emitted the tongue-shaped flows intermittently to different directions.

著者

鎌田 浩毅

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.1986, 1986

著者

鎌田 浩毅

出版者

日本地質学会

雑誌

地質学雑誌 (ISSN:00167630)

巻号頁・発行日

vol.91, no.4, pp.289-303, 1985

被引用文献数

2 12

著者

鎌田 浩毅 須田 恵理子 齋藤 武士 飯澤 功 酒井 敏

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.51, no.2, pp.168-175, 2002-02-15

参考文献数

28

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Volcanic debris avalanche is a large-scale landslide which occurs at unstable volcanic edifice and often creates horseshoe-shaped crater at its source with hummocky deposits of volcanic debris including large blocks inside. Dynamic pressure model has recently been proposed to explain flow behavior of volcanic debris avalanches: Kinetic friction of debris avalanche decreases systematically at threshold of a certain critical speed for flotation. We have done a sliding experiment using flour powder as debris avalanche matrix and metal disks that slide on a powder layer as incorporated large blocks. Sliding traces left on a powder layer showed that a disk was floating over a certain critical speed. Kinetic friction coefficients, calculated by the position of a sliding disk recorded on a digital video, become small at a higher speed which exceeds critical floating speed, and provide smaller coefficient than those of normal surface of a rigid body. The critical floating speed deduced from dynamic pressure model is consistent with our experiment. In order to verify this model as the major driving force to float megablocks incorporated commonly in a volcanic debris avalanche, critical floating speeds for two geological cases at the collapses of 1980 Mount St. Helens and 1984 Ontake, central Japan, are examined and compared with the observed flow velocities. Estimated velocities deduced from the dynamic pressure model correspond fairly well to the actual velocities. This strongly suggests that the model gives the most convincing explanation for transportation and deposition mechanism of volcanic debris avalanche.

著者

竹村 恵二 伊藤 康人 鎌田 浩毅

出版者

一般社団法人 日本地質学会

雑誌

日本地質学会学術大会講演要旨 (ISSN:13483935)

巻号頁・発行日

vol.1998, 1998

著者

鎌田 浩毅 村岡 洋文

出版者

日本地質学会

雑誌

地質学雑誌 (ISSN:00167630)

巻号頁・発行日

vol.90, no.2, pp.125-128, 1984

被引用文献数

5

著者

須藤 茂 阪口 圭一 松林 修 鎌田 浩毅 加藤 完 山本 隆志

出版者

特定非営利活動法人 日本火山学会

雑誌

火山.第2集

巻号頁・発行日

vol.29, pp.S253-S265, 1984

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Temperature measurements of the lava of 1983 in Miyake-jima in the Ako district were started fifty days after the eruption and have been continued since then. The following three kinds of temperature data have been obtained (Fig. 2). 1. Temperatures at 20 cm depth along a graveled temporary road on the clinkery surface of the lava using mercury and alcohol thermometers. 2. Temperatures at 0.5 to 2.5 m depth in iron pipes inserted into the clinker layer using thermocouples and mercury thermometers. The pipe holes were distributed along the temporary road and at scattered stations on the surface of the lava. 3. We drilled a borehole (DH-1) which penetrates through 5.5 m-thick lava into the previous ground. Temperature was measured at 10 points in the hole using thermocouples. For comparison, similar measurements in the Awabe district were made in pipes with depths up to 2.5 m (Fig. 3). These pipes were buried in the holes dug into the massive part of the lava for electric poles. The temperature data at 20 cm depth and in the pipe holes (Figs. 5-10) indicate that isothermal surfaces in the clinker layer are very complicated. This complexity is explained by rising plumes of hot vapor irregularly present in the lava field. The vapor is produced by degassing process in the massive part of the lava and comes up through newly formed cooling joints. Once a cooling joint is formed, the temperature of the massive part of the lava around the joint fell rapidly because a gas plume effectively transports the heat from the massive part to the surface. But the rate of temperature decrease varies greatly from one station to another. New plumes were formed sporadically and the temperatures of the new plumes were much higher than the decreased temperatures of the older plumes. Some older plumes died out because degassing process ended or the joints were self sealed by sublimates. It is necessary to arrange a number of observation stations and to add stations timely in order to reveal a cooling history of aa lava like the lava of 1983 in Miyake-jima. Around a plume, a convection cell was identified in the clinker layer (Figs. 16-18), which is similar to a hydrothermal convection system usually found in geothermal areas. The change of the temperature-depth profile of DH-1 with time (Figs. 11, 12) clearly shows that the lava heated the underlying previous ground. The peak shape of the profile has become broader and the depth of the maximum temperature has steadily fallen. The change of the temperature-depth profile also suggests that the upper clinker layer prevented rainfall from effective cooling of the massive part of the lava for the first 250 days. During that time, raindrops were evaporated in the clinker layer and did not reach the massive part below the clinker layer. Difference of cooling rate between Awabe lava and Ako lava may be due to the difference of the thickness of the clinker layers (Figs. 15, 19).

著者

鎌田 浩毅

出版者

公益社団法人 東京地学協会

雑誌

地學雜誌 (ISSN:0022135X)

巻号頁・発行日

vol.105, no.1, pp.Plate1-Plate2, 1996

著者

鎌田 浩毅 小林 哲夫

出版者

一般社団法人 日本地質学会

雑誌

日本地質学会学術大会講演要旨 (ISSN:13483935)

巻号頁・発行日

vol.1996, 1996

著者

鎌田 浩毅

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.1994, 1994

著者

鎌田 浩毅 小玉 一人

出版者

一般社団法人 日本地質学会

雑誌

日本地質学会学術大会講演要旨 (ISSN:13483935)

巻号頁・発行日

vol.1992, pp.63-64, 1992

著者

鎌田 浩毅 千葉 達朗

出版者

一般社団法人 日本地質学会

雑誌

地質學雜誌 (ISSN:00167630)

巻号頁・発行日

vol.101, no.12, pp.XXXXIII-XXXXVI, 1995-12-01

被引用文献数

2 1

著者

鎌田 浩毅 村岡 洋文 長谷 紘和

出版者

一般社団法人 日本地質学会

雑誌

日本地質学会学術大会講演要旨 (ISSN:13483935)

巻号頁・発行日

vol.1981, 1981

著者

宇井 忠英 井田 喜明 鎌田 浩毅 林信 太郎 川邊 禎久 加藤 幸弘 千葉 達朗 藤田 浩司 塩谷 みき

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.2002, 2002

著者

田代 俊之 久野 木順 蓮江 光男 真光 雄一郎 鎌田 浩史 星川 吉光

出版者

The Japanese Society of Lumbar Spine Disorders

雑誌

日本腰痛研究会雑誌 (ISSN:13417355)

巻号頁・発行日

vol.2, no.1, pp.22-26, 1996-12-11 (Released:2010-06-28)

参考文献数

6

被引用文献数

2

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妊娠時に腰痛を発症する女性は多い.そこで妊娠時腰痛の発症率, 臨床像, 危険因子などを調べるために, 分娩後10日以内の褥婦175例に対し, 入院中直接腰痛に対する問診および診察を行った.その結果妊娠中68%に腰痛を認めたが, その77.3%が31週までに発症していた.また30歳未満を若年群, 30歳以上を高齢群と分けると, 各群間の腰痛出現率に有意差は見られなかった.さらに, 分娩歴, 腰痛歴, 妊娠前後の体重差, 妊娠前肥満度, 新生児体重についても腰痛出現率に有意差は見られなかった.しかし, 初産婦では若年群で有意に腰痛出現率が高かった.また, 分娩直後の診察より仙腸関節部痛が18%に認められたが, 追跡調査の結果80%は1カ月以内に痛みが消失していた.

著者

鎌田 浩明 簗瀨 誠

出版者

九州理学療法士・作業療法士合同学会

雑誌

九州理学療法士・作業療法士合同学会誌

巻号頁・発行日

vol.2017, pp.105-105, 2017

著者

鎌田 浩毅 星住 英夫 小屋口 剛博

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 1987.2 (ISSN:24335320)

巻号頁・発行日

pp.85, 1987-10-05 (Released:2017-02-10)

著者

原田 桂子 鎌田 浩二 宮本 幸子 東山 祐陽 脇本 知子 有田 憲司 西野 瑞穗

出版者

一般財団法人 日本小児歯科学会

雑誌

小児歯科学雑誌 (ISSN:05831199)

巻号頁・発行日

vol.32, no.2, pp.325-325, 1994 (Released:2013-01-18)

参考文献数

1