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Volume 10 (1964)
- Issue 3-4 Pages 111-
- Issue 2 Pages 51-
- Issue 1 Pages 1-
Volume 10, Issue 1
Displaying 1-6 of 6 articles from this issue
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Seiti Yamaguti1964 Volume 10 Issue 1 Pages 1-5
Published: June 30, 1964
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESS -
Takeshi DAMBARA, Masanobu HIROBE1964 Volume 10 Issue 1 Pages 6-13
Published: June 30, 1964
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSThe precise leveling in Japan commenced in 1884, and 80 years have passed away since then. During this period, the greater part of the leveling lines was revised at least twice, and even several times on some lines. But they were too fragmentary both in region and in revision years. Therefore, in order to obtain the vertical movements of the crust in the whole land of Japan, a certain systematic course of reduction is necessary. The outline of the course of reduction adopted is:(1) To derive the secular variation of the physical height of the Tokyo datum.(2) Using this variation, to derive the secular variation of the height of each bench mark which constitutes the Tokyo loop surrounding the datum (in these bench marks, the junction marks to the adjacent loop are involved).(3) To choose a certain epoch with a range of±3 years so as to unify the revision years on the adjacent loop.(4) To read the heig of the junction bench mark corresponding to this epoch, and to make it a given condition in the reduction of the adjacent loop.(5) To extend this procedure to the next loop or net one after another. In this paper, after the general discussion on the reduction of the precise leveling, the secular variation of the physical height of the Tokyo datum is derived by using the similar variations of several bench marks which surround the datum and locate on the stable pleistocene layer of the Musashino Plateau. The numerical value is given by the relation (A).View full abstractDownload PDF (962K) -
Haruo YASUDA, Rikinosuke FUKAYA1964 Volume 10 Issue 1 Pages 14-17
Published: June 30, 1964
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThe latitudes derived from the observations of declinations of the Fundamental stars with the eight-inch Meridian Circle at the Tokyo Astronomical Observatory are compared with the latitudes derived from the observations of Tokyo's PZT. Before comparison, the latter is transformed to the values based on the ILS-system. Thus the difference between them in non-polar variation is found, amounting to 0." 078 sin (2mt+201.) in semi-annual term. It may be mainly due to the effect of the anomalous refraction caused by the semi-annual variation of the temperature in the reversing layer. In May and November, the migratory anticyclones overlay Japan, and the temperature in the reversing layer becomes higher than the normal one. In February and August the temperature becomes lower.View full abstractDownload PDF (402K) -
Yoichiro FUJII1964 Volume 10 Issue 1 Pages 18-23
Published: June 30, 1964
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSUsually, gravity anomalies are computed assuming the normal value of the vertical gradient of gravity. It is much desirable, however, that the anomaly of the vertical gradient of gravity is taken into consideration for computing the values of gravity anomaly. The writer derived a formula for calculating the gravity anomaly of the latter sense from the horizontal distribution of the gravity anomaly of the former sense accord ing to Dr. Tsuboi's successive approximation method.
If the horizontal distribution of the gravity anomaly on the sea level is expressed by
Δg0 ''=∑Amn sin cos mx sin con ny
the aimed gravity anomaly considering the anomaries of vertical gradient of gravity designated by Δg0 ''will be given by
Δg0 ''=∑(1+√m2+n2H)Amn sin cos mx sin con ny
Dr. Kumagai introduced a new idea of “ Station Bouguer Anomaly” and derived a formula for the same purpose as the writer's. But it can be proved that his formula is one of the approximations to the exact formula. In order to determine the gravity anomaly of dgo' with the accuracy better 0.1 mgal, using the writer's formula, the following condition must be fulfilled;
(√m2+n2H)2>1/10Amn
This condition is also needed for the Dr. Kumagai's method. If the condition is not fulfilled, the series which appears in the writer's formula will diverge and the gravity anomaly, Δg0 '', will not be able to be computed.View full abstractDownload PDF (673K) -
Yoichiro Fujii, Sabro KOGURE, Kazuo KITADA1964 Volume 10 Issue 1 Pages 24-35
Published: June 30, 1964
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSGravity observations were carried out by the Geographical Survey Institute in Hachijo and Torishima islands with gravimeter as a part of the synthetic geophysical investigation about Idzu-Mariana arc island in March and April, 1963. This works are separated into two parts. The one is to establish a precise fundamental gravity station in each island refered to Tokyo, G. S. I. The results are; g Hachijo-g Tokyo, G. S. I.= -39.25±0.02(m. e.) mgals (with Worden gravimeter No. 346 and La Coste and Romberg gravimeter G-29) g Torishima-g Tokyo, G. S. I.= -234.09±0.04(m. e.) mgals (with La Coste and Romberg gravimeter G-29) The other is to find the general trend of the distribution of the gravity anomalies in each island and this was performed with the one way observation method by a gravimeter. Also the observations of the vertical gradient of gravity were made at some places in both island. One of the remarkable results of the observation in Hachijo was to find a relatively negative gravity anomaly at the center of Higashiyama caldera.View full abstractDownload PDF (1190K) -
Yoichiro FUJII, Sabro KOGURE, Tsutomu SAITO, Kazuo INOUE, Ichiro MURAT ...1964 Volume 10 Issue 1 Pages 36-45
Published: June 30, 1964
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSThe Geographical Survey Institute purchased a La Coste and Romberg Geoditic Gravity-Meter Model G-29 in October, 1962. The test observations were carried out at Wakkanai, Asahigawa, Abashiri and Chitose in the Hokkaido District via Mizusawa and Sapporo in November, 1962. Another observations were made at Kyoto, Hiroshima, Kochi, Fukuoka and Kumamoto in Western Japan in January, 1963. At each station, the gravity difference from Tokyo (G. S. I.) were determined with a caribration table that was furnished by the maker. During these field work also the test observations were tried at Kakioka, Kawagoe, Hakone and so on in the neighbourhood of Tokyo. The purpose of these observations were to check the accuracy of the reading value and the reliability of the maker's calibration table and, finally, to determine the most reliable gravity value at each station. The results are; 1) Reading accuracy obtained from several observations at one station by one or several observers is less than ±0.02 mgals when the meter is set quietly at that station. 2) Reading accuracy resultant from the irregularity of the drift of the meter is less than ±0.06 mgals when the meter is transported by railway or automobile along the ratherlarge distance. 3) Mean normal drift at the gravity room in G. S. I. is +0.80 mgal per month. This. is rather large as compared with another La Coste and Romberg gravity meter but the difference of the drift according to the condition that whether the meter is set quietly at the station or transported can not be recognized. 4) The calibration factor determined by the maker's experiment in the room is ratheraccurate and the calibration error is less than 0.1%. This was mainly confirmed by the comparisons of the gravimeter results with those of the G. S. I. pendulum apparatus at; Sapporo, Mizusawa, Kakioka, Hakone, Kyoto, Fukuoka and Kumamoto.View full abstractDownload PDF (1151K)
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