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Volume 5 (1958 - 1959･･･
- Issue 3-4 Pages 63-
- Issue 2 Pages 37-
- Issue 1 Pages 1-
Volume 5, Issue 1
Displaying 1-5 of 5 articles from this issue
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Kumizi IIDA, Harumi AOKI1958 Volume 5 Issue 1 Pages 1-6
Published: August 10, 1958
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSA theoretical formula for calculating subterranian mass distribution from the gravity values at the surface is studied on the basis of Tsuboi's method. We are led to an appro ximate formula (7) or (15) expressed by linear equation with gravity value and its first and the second vertical derivatives at the surface. The coefficients of this linear combination can be determined by the way that the response of the Fourier components would be the best and the numerical coefficients are also presented under the consideration of the grid spacing or the wave length and the depth for calculation. Since the derivative calcu lation has the filtering characteristics that can be compared to that of an electric filter, its indication may be quite variable depending on the choice of spacing and pattern of the points or wave length. Then the evaluation of the vertical derivative formulas of gravity introduced in our present formula is examined by the characteristic equation concerning with wave length, with special reference to the formulas given by Elkins, Kato, and others. Thus, the subterranian mass distribution can be obtained within 10 percent errors by our formula.View full abstractDownload PDF (625K) -
Yoshibumi TOMODA, Hiroichi TAZIMA1958 Volume 5 Issue 1 Pages 7-11
Published: August 10, 1958
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSThe values of ∂g/∂z were observed at several sampling points in Japan. The anomalies in ∂g/∂z obtained from the observation were compared with that theoretically calculated from the Bouguer anomalies around the points. Differences between these two values are large as shown in the Table 1. The causes which give such differences have been investi gated. It is suggested that the main cause is the effects of topography near the observation point. Free air reduction obtained by the use of 0.3086 mgal/m customarily used will be more appropriate than that obtained by the use of actually observed value of ∂g/∂z.View full abstractDownload PDF (436K) -
Yoshibumi TOMODA1958 Volume 5 Issue 1 Pages 12-26
Published: August 10, 1958
Released on J-STAGE: March 01, 2011
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Naomi MIYABE1958 Volume 5 Issue 1 Pages 27-29
Published: August 10, 1958
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThe heights deduced by means of multiplexes were examined in actual field by leveles and the deviations in heights were worked out. The data of deviations in heights thus worked out number 576, and they are subjected to statistical study. The results obtained by the statistical study are: (i). The frequency distribution of the deviations in heights is of Gaussian type, and the standard deviation δis±5, 6 m when the whole data are taken into consideration. If, however, the deviations larger than 10 m, which might have resulted from some mistake or from local distorsion in the photographic films, were excluded, δis±3.9 rn., the data taken in this case being 540 in numberr i. e., 94% of whole data. This lead to the conclusion that the deviation in heighh will be less than 4 m at 5% level of significance, that is, about 30% of the height deduced by means of multiplexes shall be revised by the field examination survey. (ii). The median value of the deviations in heights shifts by about 2 m. in positive side. If this shift of median value is really existing, but not attributable to the personal property of operators, it may caused by the errors in the lens systems of optial appara tuses through which the topographical features are projected on the table of multiplexes, and/or by the asymmetry in the intensities of lights projected through red and blue screens, and soon. This latter fact may deserve further development of statistical and experimental study.View full abstractDownload PDF (323K) -
Masanobu HIROBE1958 Volume 5 Issue 1 Pages 30-32
Published: August 10, 1958
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSA new Askania precision theodolite with photographic reading after Gigas, which was imported from Germany in 1955 and has been used in the first order triangulation surveys, was tested using a collimeter in our laboratory, in comparison with a Carl Bamberg 27 cm precision theodolite, which is the prototype of the Askania theodolite, and a Wild 14 cm theodolite. The result has shown that the Askania theodolite is the most excellent one among these theodolites, though the all instruments are sufficient to be used for precision surveys . For the Askania theodolite the standard . deviation of single angle is 0.7", the reading error of the graduation is 0.2" and the accidental error of the graduation is 0.2". These data obtaining from the laboratory test will be useful as the fundamental ele ments for analysing systematic error, discussing accuracies and improving methods in the precise field surveys.View full abstractDownload PDF (352K)
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