地学雑誌
Online ISSN : 1884-0884
Print ISSN : 0022-135X
ISSN-L : 0022-135X
76 巻 , 6 号
選択された号の論文の6件中1~6を表示しています
  • 新野 弘
    1967 年 76 巻 6 号 p. 275-282
    発行日: 1967/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    大陸も海洋底もともに地殻上層の一部を成すが, 地球物理, 地質学上のデータから見て, その構造には著しい差異が認められている。大陸においては比重の比較的小さい物質より成る岩石が地表より相当の深度までを占めていて, その下に比重の大きい岩石があり, 海洋底では比重の小さい物質より成る堆積物や岩層はきわめて薄くなつていて, 比重の大きな岩石がきわめて海底に近づいて位置していることが知られている。大陸に接する海底部は構造上より見て, むしろ陸地に近似し, 海洋の中心に近づくに従つて海洋底の特徴が明らかとなる。
    海底の上には厚い海水の層があつて, 海底に及ぼす影響は海水という特別な溶液の性質を通して行なわれるから, 陸地の場合と異る地質現象がある。海水は陸地を蔽う大気または淡水に比べて比重が大きく, 各種の元素が塩類として溶け込み, 弱アルカリ性を呈し, 含有瓦斯量も海水の組成や物理的変化に応じ変化している。海洋水のエネルギーは波浪, 潮汐, 潮汐流, 海流等の形で認められ, これらの海水の運動が海水中に浮游する無機物有機物の移動や沈積に大きな密接な関連を示す。また海水中には各種の生物が繁殖し, 海底堆積物の生成の源を作つている。海底に堆積した物質は, 基盤岩石上においての累積時間経過の過程で変化を生ずるがある種の鉱物は固化の進行する間に生成される。
    海底にある鉱物をその所在より大別すると, 海底の堆積物中にあるものと海底の基盤を作る岩石中にあるのとに区別することができる。
    海水下にある地殻の部分を海底と呼ぶとするといくつかに区別することができる。
  • 尾原 信彦
    1967 年 76 巻 6 号 p. 283-298
    発行日: 1967/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    It is difficult for an engineering geologist who participates in exploitation on a large scale to learn an underground condition of alluvial plains, without plenty knowledge of soil mechanics, hydrodynamics, geophysical prospecting, boring techniques and so on. Practical utility is the most significant essence for the establishment of engineering geology. The writer intends to approach to the aim at this stage, having a perfect command of geology, together with fundamental knowledge of geophysics, geochemistry and civil engineering.
    The writer has investigated the 25 areas among the extensive littoral lowland in Japan by way of boring method during these seven years, in order to learn the underground condition. He has known the fact that the bore hole attains to the Tertiary formation within the average depth of 150 200 meters even in the deepest case ; that is an unconsolidated deposit has accumulated from the earth surface down to the depth, underneath which a harder formation has been found. These researches have utilized the newer method of prospecting, such as electric prospecting, lifting-up subterranean water, soil mechanic test and chemical analysis of pore water of boring cores etc. He describes the nature of the underground structure of the districts surveyed, illustrating a few examples.
    Then the writer explains means for study necessary for the localization of industry upon a littoral lowland. It is a important problem whether the ground of sites can be borne against the weight of the building of factories or not. There are soft grounds, the bearing-power of which are less than 10t per m2, everywhere in a littoral plain. An engineering geologist has tried to search for various kinds of prospecting methods, which occupy an indispensable part. The writer explains a few techniques for prospecting bearing-power of grounds, viz, standard penetration test (N-value method) and sounding method of Sweedish mode etc.
    Measurement of void water-pressure in a stratum can determine stability of grounds or solve land subsidence. The writer recommends and explains an instrument named Sakata P. P. R. void pressure meter fitting for in situ test, introducing a few instances of success.
    Engineering geologist must make efforts for counter-measures in the prevention of disasters in a littoral lowland, such as land subsidence in the main industrial regions and quick sand phenomenon after a severe earthquake. Since the writer has touched on the character and origin of the two phenomena previously, he has been able to account for a detail status quo of the studies in Japan.
  • 蔵田 延男
    1967 年 76 巻 6 号 p. 299-312
    発行日: 1967/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    I believe, it is useful to make a note of various memorandums of our seniors in the field of earth science.
    In this materials, fifteen memorandums concerning the groundwater explorations done by our honourable seniors are introduced.
    In those bays, many cities in this country wished to investigate the groundwater situation for constructing of city water source by the deep well method which had been in high opinion.
    They are Toyama, Toyohashi, Nagano, Yokkaichi, Hamamatsu and Shizuoka cities by Mr. Oinoue, Tokorozawa town and Numazu city by Mr. Ihara, Akashi city and Tamazu village in the suburbs by Mr. Kinoshita, etc.
  • 秋岡 武次郎
    1967 年 76 巻 6 号 p. 313-321
    発行日: 1967/12/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 松本 達郎
    1967 年 76 巻 6 号 p. 322-328
    発行日: 1967/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    This is a digest of the reports on the IUGS Commission on Geochronology, giving some explanations of the name, purpose, organization, and recent activities of the Commission. Activities of the National Committee on Geochronology in Japan are also reported.
  • 門村 浩
    1967 年 76 巻 6 号 p. Plate1-Plate2
    発行日: 1967/12/25
    公開日: 2009/11/12
    ジャーナル フリー
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