PRECISE RELATIVE MFASUREMENTS OF GRAVITY IN KINKI DISTRICT, JAPAN

DOI IR HANDLE Web Site Open Access

Bibliographic Information

Other Title
  • 近畿地方における重力の精密相対測定
  • 近畿地方における重力の精密相対測定〔英文〕
  • キンキ チホウ ニ オケル ジュウリョク ノ セイミツ ソウタイ ソクテイ エ

Search this article

Abstract

Gravity measurements have repeatedly been carried out in the area around Lake Biwa since 1971 in order to detect the secular change of gravity. In addition, through the examination on characteristics of LaCoste & Romberg gravimeters, we proposed the method of measurement at the stations with almost equal gravity value in order to carry out the gravity measurement more accurately. And therefore, another precise gravity measurement has been carried out at stations where the gravity value is almost equal to that of reference station (Geophysical Institute of Kyoto University; 979.70775 gals), along the levelling route in the area covering Lake Biwa and the Kii Peninsula since 1972. Besides them, the precise gravity measurement has also been carried out at stations with the gravity value 979.686 gals in due consideration of their distribution. The accuracy of the results was investigated in many points of view, and it was asc.ertainecl to be usually about 10 μgals in standard deviation. The results obtained the gravity measurements were compared with the results obtained by levelling surveys, by water level observations of the lake, by oceanic tidal observations, by underground water level observations and by geodetic control surveys. The gravity change was not in a good correlation with the vertical movement obtained from levelling surveys, but it was with the movements obtained from the observations of water level and oceanic tides. The precise gravity measurement is less accurate than the levelling survey when the vertical movement is to be obtained in a short distance. However, it is a very great advantage that the precise gravity measurement can directly connect two stations which are located far apart. The levelling survey cannot realize this advantage, while the observations of water level and oceanic tides have this advantage. The results of the present investigations may be ascribed to this advantage. On the other hand, the gravity increase was found at the tip of the Kii Peninsula, and this may be partly explained by the areal contraction caused by the push of the Philippine Sea Plate.

Journal

Keywords

Details 詳細情報について

Report a problem

Back to top