Journal of the Geodetic Society of Japan

New Model of the Tokyo Surface Ship Gravity Meter (Part 1)

Yoshibumi TOMODA, Kin-ichiro KOIZUMI

1972 Volume 18 Issue 1 Pages 1-7
Published: July 25, 1972
Released on J-STAGE: July 05, 2011

DOIhttps://doi.org/10.11366/sokuchi1954.18.1

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The T. S. S. G. is now widely used for gravity measurement at sea on board research ships of Ocean Research Institute or of Hydrographic Office, Maritime Safety Agency. Though many parts, data processing method has chiefly been improved, but its essential part remained unchanged because it has been continuously working at sea. It has passed about 10 years since the first model of T. S. S. G. was constructed, and we are now building a new model aiming to make more accurate and more reliable one. In this report, problems which we met with the old models are summarized, and an outline of the new model will be mentioned.

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Deformation of the Rhombus Base Line at Mitaka

Naomi FUJITA

1972 Volume 18 Issue 1 Pages 8-16
Published: July 25, 1972
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.11366/sokuchi1954.18.8

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The surveys of the rhombus base line at Mitaka, Tokyo, amount to 33 in number since 1916. From the results the followings are clarified.(1) The deformation of the rhombus at Mitaka is representative of the crustal movements in the southern Kanto district.a. Before and after the Great Kanto Earthquake The strain change in Mitaka rhombus base line (1922-1923);ε1=36X10^-6 (N5°W)ε2=-7X10-^-6 (Fig. 3)The strain change at Mitaka obtained from the geodetic data (189-.1925) Using the first and supplementary triangulations around Mitakaε1=25X10^-6 (N2°W)ε2=4X10^-6 Using the most likely fault model for the geodetic data in the southern Kanto districtε1=12X10^-6 (N8°E )ε2=-4X10^-6 (Fig.4 )b. After the Earthquake to the present (1925-1971)The strain change at Mitaka:ε1=7X10^-6 ε2=-20X10^-6 (N28°W) (Fig. 3) The strain change in the southern Kanto district;N-S contraction and NW-SE contraction prevail in Boso peninsula and around Sagami bay respectively, lε2l°2X10^-5 and ε1-ε2°3X10^-5 being in both areas. (Fig. 5 )(2) It seems likely that there is a strong correlation between the anomalous areal deformation at Mitaka and the occurrence of earthquakes with intensity more than V(>80 gal) at Tokyo, as shown in Figs. 6 and 7. There exist, however, the discrepancies of patterns in the areal deformation and the maximum shear, as shown in Figs. 2 and 8.

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On Precise Gravity Measurement at Stations of Small Gravity Difference (Part 1)

Ichiro NAKAGAWA, Mikio SATOMURA

1972 Volume 18 Issue 1 Pages 17-22
Published: July 25, 1972
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.11366/sokuchi1954.18.17

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Precise gravity measurement was carried out again at 13 stations, where gravity difference from the Gravity Station of Geophysical Institute of Kyoto University is smaller than 1 mgal, along the levelling route of the Kui Peninsula, by means of 3 LaCoste &" Romberg gravimeters (model G) in March 1972. Through the back and forth measure-ment (3 days per each way), its accuracy was obtained to be about ±0.01 mgal. Prior to the measurement, it was examined whether the reading value is affected by voltage change of the connecting battery or not. Its results are also described in the present paper.

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On Secular Change of Gravity near Lake Biwa.ko

Ichiro NAKAGAWA, Mikio SATOMURA, Tokio ICHINOHE, Norihiko SUMITOMO

1972 Volume 18 Issue 1 Pages 23-29
Published: July 25, 1972
Released on J-STAGE: July 05, 2011

DOIhttps://doi.org/10.11366/sokuchi1954.18.23

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Gravity measurements have repeatedly been carried out several times to detect secular change of gravity near the area of Lake Biwa-ko since 1950. Results obtained by means of LaCoste & Romberg gravimeters in 1964, 1967, 1970 and 1971 show that gravity value has been increasing by about 0.1 mgal during several years in the southern part of the both shores of the Lake Biwa-ko. Levelling surveys in the area concerned show the similar tendency as the gravity measurements.

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Report on the 15th General Assembly of the IUGG

1972 Volume 18 Issue 1 Pages 30-36
Published: July 25, 1972
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.11366/sokuchi1954.18.30

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Operational Method for the Stokes Integration and its Application

Yukio HAGIWARA

1972 Volume 18 Issue 1 Pages 37-39
Published: July 25, 1972
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.11366/sokuchi1954.18.37

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Gravity Survey near the Yanagase Active Fault

Mikio SATOMURA

1972 Volume 18 Issue 1 Pages 40-42
Published: July 25, 1972
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.11366/sokuchi1954.18.40

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Yanagase fault is located in the northeast side of Lake Biwa-ko, and it is one of the ac-tive faults. In order to investigate its move-ment, levelling surveys, gravity surveys and electro-optical distance measurements have repeatedly been made in the area covering the Yanagase active fault zone. As the fault re-covered by sediments, its position is not clear at a glance. Gravity survey was carried out by means of a LaCoste & Romberg gravimeter in order to examine the fault position as accurately as possible. The result obtained is described in the present paper.

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[title in Japanese]

[in Japanese]

1972 Volume 18 Issue 1 Pages 43
Published: July 25, 1972
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.11366/sokuchi1954.18.43

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