Journal of the Geodetic Society of Japan
Online ISSN : 2185-517X
Print ISSN : 0038-0830
ISSN-L : 0038-0830
Volume 30, Issue 2
Displaying 1-9 of 9 articles from this issue
  • Minoru TANAKA, Seiichi KAKINUMA, Toshihiro KOSUGE, Hiromi NAKANO
    1984 Volume 30 Issue 2 Pages 75-86
    Published: August 25, 1984
    Released on J-STAGE: September 07, 2010
    JOURNAL FREE ACCESS
    In a precise leveling survey, height dependent errors often arise on a mountain slope. They consist of rod calibration error and refraction error. In order to detect these errors, it is necessary to carry out the survey, first, using the leveling staves the scale bands of which have known and small temperature expansion coefficient (hereafter, TEC) and, second, measuring the air temperature gradient near the ground surface at each survey point for the correction of refraction. For this purpose, two sets of staves were made from super-invar and new superinvar. The original design of which was done by one of the authors (TANAKA). This was carried out under the cooperative research of the Research Institute of Electric and Magnetic Alloys and Sokkisha. Co. Ltd. The bands of staves have the TEC of 0.55 × 10-6/°C and -0.1 × 10-6/°C for super-invar and new super-invar, respectively. Their graduation errors are within 15 μm/3 m. In order to test the new staves, comparison surveys were carried out two times, each time the survey was done by the different two teams, near Ito, eastern part of Izu Peninsula. In the survey, one test team used the new staves and the other team ordinary ones. As the result, the height dependent correction amounts to 4 mm/100 m was detected. On the other hand, the height dependent error 6.7 mm/100 m was detected by treating the recent survey results statistically. In order to understand the difference of height dependent error in the test result and the statistical one, it is necessary to make more research on the refraction together with the effect of wind turbulence. It is concluded that in order to reduce the correction value less than 1 mm/100 m, the accurate control of staves is the most important in the precise leveling. It is also possible to eliminate the refraction error by keeping the sight length short.
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  • Naosuke SEKIGUCHI
    1984 Volume 30 Issue 2 Pages 87-91
    Published: August 25, 1984
    Released on J-STAGE: September 07, 2010
    JOURNAL FREE ACCESS
    BROUWER [1] proposed a model for the irregular variations of the Earth's rotation, regarding it as the results of cumulative small rate changes. It is found that this model is valid for time range about from 50 days to 50 years.
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  • Yukio HAGIWARA
    1984 Volume 30 Issue 2 Pages 92-106
    Published: August 25, 1984
    Released on J-STAGE: September 07, 2010
    JOURNAL FREE ACCESS
    Suppose an arbitrary function expressed in a surface spherical harmonic expansion series when the pole is translocated at an arbitrary point on the surface of a sphere. The coefficients of the expansion series are functions of the latitude and longitude of the translocated pole. GANEKO [6] has derived the general transformation formula of spherical harmonic expansion coefficients in a form of the modified Jacobi polynomials. It can be applied to theoretical problems of geodesy and geophysics including the translocation of the polar axis. This paper shows a simple method for deriving GANEKO's transformation formula and its inverse one, with their applications to the global geoidal height.
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  • Minoru TAZIMA, Norihisa MATSUMOTO, Masaru KAIDZU
    1984 Volume 30 Issue 2 Pages 107-113
    Published: August 25, 1984
    Released on J-STAGE: September 07, 2010
    JOURNAL FREE ACCESS
    As a part of the earthquake prediction project, GSI is recently conducting leveling surveys four times a year in the Omaezaki peninsula. Through this frequent survey, it was shown that the Omaezaki peninsula uplifts and subsides once a year. Among possible causes, the elastic deformation through buoyancy effect was taken as the most important mechanism that causes the annual variation of the elevation of the peninsula. The vertical motion estimated through two dimensional FEM model is in the same order of what was observed.
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  • -ln Relatiion to Geologic Structures-
    Mohamed G. El-IBIARY
    1984 Volume 30 Issue 2 Pages 114-121
    Published: August 25, 1984
    Released on J-STAGE: July 05, 2011
    JOURNAL FREE ACCESS
    The African continent has significant gravity anomalies delineating its coastal basins as well as those of the East African Rift System. The gravity anomalies in Egypt reflect more or less the subsurface geological structures. The northern coastal plains, the Nile Canyon, the Arabu-Nubian shield in the Eastern Desert and the plain Western Desert with its magnificent oases, all show their meaningful Bouguer anomalies. The Red Sea, the Gulf of Suez and the Gulf of Aqaba, as a unique structural feature, show Bouguer anomalies indicating simple rift structures.
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  • Izuo OZAWA
    1984 Volume 30 Issue 2 Pages 122-130
    Published: August 25, 1984
    Released on J-STAGE: July 05, 2011
    JOURNAL FREE ACCESS
    The observation of the extensions of the crust has been performed in the three orthogonal directions, they are in the vertical, in S 38°W and in S 52°E in the old Osakayama Tunnel since around 1970. Then, the dilatational strain has been obtained by summation of these observed extensions. The secular change of the dilatational strain was much smaller than each extension. But, the annual deviations of the dilatations from the secular average (standard) change are as large as those of each extension. The partial correlation coefficient between the annual deviations and the frequency of the felt earthquake at Kyoto city was fairly large value (-0.438). The forerunning compressions were usually observed in the time of the heavy precipitations which rained after few precipitations. It is interpreted that this forerunning compression is caused by the load of the precipitation and by the water pressure of the saturated water in the shallow part of the ground.
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  • -Its Application for the Bouguer Anomaly Distribution in Fukaya Area-
    Ko NAGASAWA
    1984 Volume 30 Issue 2 Pages 131-145
    Published: August 25, 1984
    Released on J-STAGE: March 01, 2011
    JOURNAL FREE ACCESS
    Geodetic measurements are usually carried out at a number of randomly spaced points on the ground. Hence the data are obtained for these survey points. When we want to deduce the corresponding values for other points among them, it is necessary to smooth and interpolate those irregularly spaced survey data in two-dimension. In the several methods for this purpose, the one employing B-spline seems the most convenient and appropriate for the geodetic data. In this paper, first, we explain the method for two-dimensional smoothing and interpolation with B-splines and, second, we apply it to the Bouguer anomaly data in Fukaya area. An obtained contour map is also given. From the map, we can see the interpolation is reasonably done except for its boundary area. This is because the data are sparsely distributed in the area.
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  • Torao TANAKA, Keichi KASAHARA, Kazuaki NAKAMURA
    1984 Volume 30 Issue 2 Pages 146-149
    Published: August 25, 1984
    Released on J-STAGE: September 07, 2010
    JOURNAL FREE ACCESS
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  • The Course of Geodesy
    Ietsune TSUBOKAWA
    1984 Volume 30 Issue 2 Pages 164-168
    Published: August 25, 1984
    Released on J-STAGE: September 07, 2010
    JOURNAL FREE ACCESS
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