著者

西村 蹊二 斉藤 祥 谷岡 誠一 門脇 淳

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.86, no.6, pp.346-363, 1977-12-25 (Released:2009-11-12)

参考文献数

20

被引用文献数

1

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Detailed and intensive investigations have been carried out on the abrupt failure of submarine slope of a small island, Shin-jima, in Kagoshima Bay, Kyushu on April 1, 1975 by the joint research group of Geographical Survey Institute of Japan, Japan Maritime Safety Agency and Geological Survey of Japan under the sponsorship of Japan Science and Technology Agency.The Shin-jima island emerged from water at the great eruption of adjacent Sakurajima Volcano in 1779 to 1780 (An-ei Eruption) as one of central corns of Aira Caldera (MATSUMOTO, 1933). The island gradually reduced its exposed area by continuous wave erosion to form truncated configuration, being surrounded by broad, shallow, flat tidal bench.Geologically the island is composed of the latest Pleistocene to the earliest Holocene thick loose pumice deposits with intercalations of silt and clay showing inner bay facies. These formations are strongly faulted by eastwest faults. The surface of the island is covered with thin shell bed dominantly composed of Ostrea and andesitic lava. The flat bench around the Shin-jima consists of recent, loose pumiceous drift sand deposits derived from the island by wave erosion.The failure of the slope now in concern occurred at the spit of the southern tip of the island, where thickness of drift sand deposits attains at most about 35 meters according to sonic prospecting and borings at the spit. It was caused by submarine landslide in the thick, loose drift sand deposits. Volume of the slide mass amounts approximately 265, 000 cubic meters.The spit had formed steep submarine slope near critical angle by abundant supply of very loose drift sand from northern part of the island before the failure occurred. Neither sensible earthquakes nor volcanic activities of the Sakurajima which might have given significant effects to submarine landslide are observed and recorded in seismometer around the crucial moment of the failure.Therefore, the cause of the landslide is considered that the increase of load resulted from the deposition of drift sand attaining about 8, 400 tons in volume atop of the slope brought about decrease of safety factor of the slope to make it slide. Wave pressure seems to have triggered the slide because safety factor decreases about 20 % when fluctuation of pressure at the bottom caused by wave agitation is taken into account.

著者

中野 峰生 五十嵐 敦 李 俊〓 大橋 一之 門脇 淳

出版者

Japanese College of Surgeons

雑誌

日本外科系連合学会誌 (ISSN:03857883)

巻号頁・発行日

vol.28, no.1, pp.82-86, 2003-02-28 (Released:2009-08-13)

参考文献数

10

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当院に受診した騎手候補生の馬による外傷を集計し, 受傷機転・部位・原因などとその事故防止対策について検討した。当院を受診した騎手候補生は43名で, 提示した2症例以外は外来治療が可能な軽症例だった。受傷原因は落馬 (55%) が最も多かったが, 次いで乗馬中以外での馬の取り扱い時の事故 (31%) であった。受傷部位は下肢 (41%) および頭部・顔面 (20%) が多く, 乗馬外傷を繰り返して起こす者 (21%) も比較的多かった。また, 騎手候補生は入校後6カ月以内に受傷していることが圧倒的に多かったことから, 馬に関する安全教育を入校直後から指導徹底し, 防護用の服や靴を使用すべきであると考えられた。