地学雑誌
Online ISSN : 1884-0884
Print ISSN : 0022-135X
ISSN-L : 0022-135X
87 巻 , 5 号
選択された号の論文の9件中1~9を表示しています
  • 西田 史朗
    1978 年 87 巻 5 号 p. 237-249
    発行日: 1978/10/25
    公開日: 2009/11/12
    ジャーナル フリー
    Modern calcareous nannoplanktons have an important role in marine food chain as a primary producelr. Fossils nannoplankton played an important part of the Mesozoic and Cenozoic biological world, and are now accepted as a very useful and accurate index fossil from the Jurassic to Recent Period.
    In this article recent advance of nannoplankton micropaleontology and biostratigraphy were briefly reviewed. And a calcareous nannoplankton biostratigraphy of the Upper Cenozoic sections in Japanese Pacific coast was presented.
    In the sections drastic changes of some calcareous nannoplankton species are recognized clearly ; that is, the first appearances of Reticulofenestra japonica, Gephyrocapsa caribbeanica, Gephyrocapsa oceanica, Gephyrocapsa protohuxleyi and Emiliania huxleyi in ascending order, and the disappearances of Sphenolithus abies, Reticulofenestra pseudoumbilica, Discoaster surculus, Discoaster pentaradiatus, Discoaster brouweri, Cyclococcolithus macintyrei. Cyclolithella annula, Reticulofenestra japonica, Reticulofenestra pacifica and Pseudoemiliania lacunosa in ascending order.
    Based on the first appearances of these species, we can distinguish five calcareous nannoplankton zones in Japan ; that is, Reticulofenestra pseudoumbilica Zone, Reticulofenestra japonica Zone, Reticulofenestra pacifica Zone, Gephyrocapsa oceanica Zone and Emiliania huxleyi Zone in ascending order.
    Range chart of some important species and calcareous nannoplankton zonation are presented in figure 3, and a stratigraphic correlation is also shown in figure 4.
  • 松田 磐余, 和田 諭, 宮野 道男
    1978 年 87 巻 5 号 p. 250-259
    発行日: 1978/10/25
    公開日: 2009/11/12
    ジャーナル フリー
    The relation between subsoil condition and the collapse rate of wooden houses has been examined in Yokohama City where was severely damaged by the Great Kanto Earthquake in 1923. The authors have made a landform classification map (Fig. 1), a geologic section in the coastal lowland (Fig. 2), a contour map showing the basal landform of the post-Würm deposits (Fig. 3) and a distribution map of the collapse rate of wooden houses (Fig. 4) in order to provide themselves with the basic data for analysing the relation. The following results have been obtained from the statistical and the seis-mologic engineering analyses on these figures and many bore hole records used to construct Figs. 2 and 3.
    (1) The relation between the collapse rate (P %) of wooden houses and the thickness (X meter) of the post-Würm deposits excluding Basal Gravel (BG ; cf Fig. 2) is shown in Fig. 5. The regression line of
    P=2.7 X-17.2
    with the correlation coefficient of 0.76 has been derived from a method of least squares.
    (2) After classifying the post-Würm deposits into seven parts of X1 (uppermost deposits ; mainly filled up soils), X2 (humus), X3 (clayey deposits with N-value of 5 or less), X4 (clayey deposits with N-value of 6 or more), X5 (sandy deposits with the N-value of 10 or less), X6 (sandy deposits with the N-value of 11 or more) and X7 (sand and gravel), the collapse rate (Pc %) of wooden houses has been related to the thickness of each of these seven parts by means of multiple regression analysis. As a result, the equation with the multiple regression coefficient of 0.87,
    Pc=-0.99-2.05 X1+3.30 X2+2.33 X3+1.42 X4+1.99 X5+2.33 X6-0.05 X7
    has been obtained (Fig. 6).
    (3) On the basis of the results of frequency response analysis, the relations among the period and the value of the maximum response magnification factor and the collapse rate of wooden houses have been examined. As a result, it has been clarified that the collapse rate of wooden houses is largely determined by the period of the maximum response magnification factor rather than the value of that (Figs. 9 and 10).
  • 春山 仁
    1978 年 87 巻 5 号 p. 260-270
    発行日: 1978/10/25
    公開日: 2009/11/12
    ジャーナル フリー
    “Magnetic Maps 1975 of the Antarctic” has been compiled by the Geographical Survey Institute (GSI). Most of its data have been sent to GSI by countries joining to the Scientific Committee on Antarctic Research (SCAR) at its request through SCAR to be submitted to the spherical harmonic analysis.
    Distribution of the earth's magnetic field and its annual change are represented in seven maps corresponding to each component by the illustration of isomagnetic and isoporic lines respectively. Residual total intensity at the observation points is shown on the eighth map.
    Location of the south magnetic pole is obtained. It has been moving on the Continent toward north or northwest direction and is now located at a point off the coast of Adelie Land. It appears that the dipole moment of the earth's magnetic field is still decreasing at an approximately constant rate.
  • 小林 貞一
    1978 年 87 巻 5 号 p. 271-273
    発行日: 1978/10/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 小林 貞一
    1978 年 87 巻 5 号 p. 274-275
    発行日: 1978/10/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 日本地学史資料調査委員会
    1978 年 87 巻 5 号 p. 276-305
    発行日: 1978/10/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 佐藤 正
    1978 年 87 巻 5 号 p. 306-307
    発行日: 1978/10/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 藤井 昭二
    1978 年 87 巻 5 号 p. 307-308
    発行日: 1978/10/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 吉田 栄夫
    1978 年 87 巻 5 号 p. Plate1-Plate2
    発行日: 1978/10/25
    公開日: 2009/11/12
    ジャーナル フリー
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