地震 第2輯
Online ISSN : 1883-9029
Print ISSN : 0037-1114
ISSN-L : 0037-1114
10 巻, 3-4 号
選択された号の論文の7件中1~7を表示しています
  • 松島 昭吾
    1957 年 10 巻 3-4 号 p. 113-122
    発行日: 1957/12/25
    公開日: 2010/03/11
    ジャーナル フリー
    In this paper, creep tests made on granite specimens under a uniaxial compressional pressure are reported. It has been found, as previously inferred, that the flow rate in lateral direction becomes larger than that in axial direction with increasing load. Near or in the fracture range, the lateral flow becomes some hundred times as large as the longitudinal one. This result conforms in tendency to the variation of Poisson's ratio with load which was reported in the previous paper.
    Referring to the recovery and stress-strain curves, it is suggested that granites show different behaviors simultaneously in different directions under a uniaxial compression; that is elastic in the direction of the applied stress and plastic in the direction perpendicular to it.
  • 加藤 昭七郎
    1957 年 10 巻 3-4 号 p. 123-140
    発行日: 1957/12/25
    公開日: 2010/03/11
    ジャーナル フリー
    Assuming the fluid motion of vT1°-type (expression (3.1) in §3), we have studied here the time characteristics of self-exciting fluid dynamos. As a result of theoretical calculations, it has been found that three magnetic fields expressed by three surface spherical harmonics Ymn-1, Ymn and Ymn+1((n, m)-harmonics in §3) can coexist independently of other magnetic fields. These three magnetic fields oscillate concurrently in intensity quasi-periodically with time, the frequency being proportional to order m, fluid velocity and depth of the fluid layer. The westward drift of the earth's magnetic field and also the reversal of the magnetic field of the sun may be well explained by the above results. The periodical dynamo presented here may also be appropriate as a model for magnetic variable stars.
  • 佐藤 良輔
    1957 年 10 巻 3-4 号 p. 141-153
    発行日: 1957/12/25
    公開日: 2010/03/11
    ジャーナル フリー
    Reflection and refraction of elastic waves at a discontinuous boundary in transmitting medium have been studied by many authors since 1899. Most of them have assumed that density or elastic constant of the medium vary discontinuously (mathematically) at the boundary. While there can be little doubt that very sharp discontinuities exist in the earth, it will be better to consider that physical properties of materials in the immediate vicinity of the “discontinuity” vary continuously in actual cases. In such cases, the most pertinent transfer of energy among the waves concerned takes place near the boundary, say, within a few wave-lengths from it, and no theory can be adequate without referring to the sharpness of discontinuity as compared with the wave-length.
    K. Sezawa and K. Kanai, in 1935, and A. Wolf, in 1937, are the only two who investigated the effect of sharpness of discontinuity on reflection and refraction phenomena. Their studies, however, were confined only to vertical incidence of waves, (although, in the latter, some qualitative statements were made about the general case), with simplifying assumptions that densities are the same everywhere and rigidity or velocity in the intervenient layer varies linearly with depth.
    In this paper, the present writer has investigated reflection and transmission of elastic waves at “discontinuity” for the incidence of SH-waves with various glancing angles, supposing that there is an invervenient layer of thickness H between two different media. In the intervenient layer, both density and rigidity vary continuously but steeply from the corresponding values of the upper medium to those of the lower one. He has found that the reflected wave is considerably affected by the existence of the intervenient layer if the wave-length of incident wave is very small compared with the thickness of the layer, but the transmitted wave is not affected very much.
  • 鈴木 次郎
    1957 年 10 巻 3-4 号 p. 154-160
    発行日: 1957/12/25
    公開日: 2010/03/11
    ジャーナル フリー
    A complete expression of dynamical characteristics for electromagnetic seismographs with no electric amplifier has been derived by Tazime. In this paper the same expression is deduced in another way, which is more familiar to seismologists. The method is conducive to easy understanding of physical meanings of the expression. Further, the expression is reduced to one of practical convenience. The new expression is written in terms of usual constants for galvanometer, i. e., period, coil resistance, critical damping resistance, and sensitivity.
  • 片岡 明雄, 小栗 幹男
    1957 年 10 巻 3-4 号 p. 161-162
    発行日: 1957/12/25
    公開日: 2010/03/11
    ジャーナル フリー
  • 矢橋 徳太郎
    1957 年 10 巻 3-4 号 p. 162-164
    発行日: 1957/12/25
    公開日: 2010/03/11
    ジャーナル フリー
  • 鈴木 次郎, 石田 治子
    1957 年 10 巻 3-4 号 p. 164-165
    発行日: 1957/12/25
    公開日: 2010/03/11
    ジャーナル フリー
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