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Volume 18 (1972)
- Issue 4 Pages 161-
- Issue 3 Pages 99-
- Issue 2 Pages 49-
- Issue 1 Pages 1-
Volume 18, Issue 3
Displaying 1-7 of 7 articles from this issue
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Yukio HAGIWARA1972 Volume 18 Issue 3 Pages 99-103
Published: December 30, 1972
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThe infinite series of the expansion of Stokes' function in Legendre polynomials converges very slowly. Molodenskii et al [1] introduced a polynomial SN of degree less than N in order to improve the convergence of the series. They also applied derivatives of SN to the truncation of the deflection of the vertical as an approximation of Vening Meinesz' function. However, the derivatives of SN should not be treated as a polynomial which best fits Vening Meinesz' function. In the present paper, the author proposes the bestfitting polynomial for Vening Meinesz' function. The problem treated here is, in other words, an extension of the problem pointed out by de Witte [2].View full abstractDownload PDF (306K) -
Noboru INOUCHI, Katsumi KANO, Yoichiro FUJII1972 Volume 18 Issue 3 Pages 104-111
Published: December 30, 1972
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSSince 1963, the Geographical Survey Institute has been engaged in gravity observations in Ooshima Island, one of the most active volcanoes in Japan. This is the second report and gives the results of observations made in 1969 and 1972. At Gojinka Chaya, very close to the crater of Mt. Miharayama, we have six gravity values obtained at different period. By comparing these values, it is proved that gravity at Gojinka Chaya was gradually decreased after the great eruption of 1950 till 1967. This decrease reaches to 0.9 mgal. During the period from 1967 till now gravity begins to increase by 0.1 mgal. The authors emphasize the importance of repeated gravity observations also in future in order to get useful informations about volcanic activities in this volcano.View full abstractDownload PDF (701K) -
Shigeyasu ONO, Noboru INOUCHI1972 Volume 18 Issue 3 Pages 112-122
Published: December 30, 1972
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThe system of computing astrogravimetric leveling uses an electronic computer for much of the calculation. The average anomalies of the grid squares are used as field data. When calculating gravimetric corrections, the gravity data extending to a limited radius from the middle point between the two astronomical points are taken into account. On Eremeev-Ostach's model the calculations were carried out. Sufficient results were obtained.View full abstractDownload PDF (700K) -
Shigeyasu ONO1972 Volume 18 Issue 3 Pages 123-133
Published: December 30, 1972
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSEstimates are given of the errors resulting from the use of only the anomalies of the limiting area in astrogravimetric leveling and in the interpolation of the deflection of the vertical, in which the area of integration of the anomalies is limited by a eartain distance from each astronomical point and from the computation point. In this case, the errors depending on the root mean square anomaly near the boundary of the area of integration of the anomalies are reduced by half as compared with the conventional one. The errors, however, also depend on the r. m. s. values of the first and higher derivatives of gravity anomaly with respect to the direction joining the two astronomical points, and to the direction of interpolation, near the same boundary.View full abstractDownload PDF (633K) -
Takeshi DAMBARA1972 Volume 18 Issue 3 Pages 134-140
Published: December 30, 1972
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSIn general, simultaneous adjustment of leveling net which is composed of many loops is considered to give most plausible result. But, when one loop involves large error or closure, simultaneous adjustment not always gives standard result. In order to see the distribution of closure correction, some calculations are made using simple models of leveling net in this paper. In Fig. 1 (C), a method of representation of correction distribution is shown. All results of calculation are illustrated in Figs. 2, 3-1, 3-2 and 3-3. Using actual result of survey which was made in 19501952 (Table II), 9 cases of adjustment (in Fig. 4) are calculated. Deviations of 8 cases from simultaneous adjustment (case 1) at junction bench marks are shown in the upper row of Fig. 5. Clear deflection is seen in this result. This deflection is caused by the large closure of loop II. In such case, a method to take the mean of all cases of loop combination is proposed. Gaussian distribution of deviations of each case from this mean value is obtained, which is shown in the lower row of Fig. 5.View full abstractDownload PDF (563K) -
Ko NAGASAWA1972 Volume 18 Issue 3 Pages 141-148
Published: December 30, 1972
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThe cross suspension pendulum system has been alreadly adopted as key mechanismm in the detector of TEM tiltmeter. As the pendulum system has special character that magnifies the tilting of its support, it will be applicable not only to tiltmeters but to other instruments which detect small amount of displacement. In this paper, the various natures of the cross suspension pendulum, such as its equilibrium position, sensitivity to tilting, period of the pendlum and their relations are theoretically treated. In these relations, it is noticeable that the sensitivity is approximately propotional to the square of the period of the pendulum on condition of normal use.View full abstractDownload PDF (476K) -
Michio YANAGISAWA1972 Volume 18 Issue 3 Pages 149-153
Published: December 30, 1972
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSDownload PDF (4150K)
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