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Volume 34 (1988)
- Issue 3-4 Pages 157-
- Issue 2 Pages 97-
- Issue 1 Pages 1-
Volume 34, Issue 1
Displaying 1-8 of 8 articles from this issue
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-Merit of Revision of Scale Constant of Gravimeter-Yoshihiro OKUBO, Shinji KANAI, Yoshiteru KONO1988 Volume 34 Issue 1 Pages 1-9
Published: June 25, 1988
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSGravimetric connections of the first order gravity stations were carried out in and around the Kitakami district, Northeastern Japan, by means of the LaCoste & Romberg gravimeter (model G) No. 348 taking the first order gravity station in Kanazawa as a reference one. The maximum gravity difference between Kanazawa and stations amounted up to about 500 mgals. Scale constant of the gravimeter was revised through the project of the gravimetric connection along the Circum Pacific Zone by using nine gravimeters, which was carried out during 1980 to 1983. Observed gravity values calculated by using the original scale constant produced maximum errors about 0.3 mgal. The revised scale constants reduced them to only -0.005±0.024 mgal.View full abstractDownload PDF (843K) -
Masao KOMAZAWA1988 Volume 34 Issue 1 Pages 11-23
Published: June 25, 1988
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSA computation program of terrain correction by assuming the annular prism model was made to be applied to the gravity station not only on the ground but also in the tunnel, on the bottom of the sea, on the surface of the sea or in the air. The calculation region of terrain correction is composed of following four regions. The extreme-near region including gravity station is from 0 m to 500 m, the near region is from 500 m to 4 km, the intermediate region is from 4 km to 16 km, and the far region is from 16 km to 60 km. At first, three kinds of terrain data, which are read from grids of latitude and longitude (7.5X11.25" (near), 30"X45" (intermediate), 2'X3' (far)), are transf omed into UTM coordinate and stored in an external memory device (disk). At next stage, three kinds of new terrain mesh data (mesh size; 125 m (near), 500 m (intermediate), 2km (far)) are formed from three kinds of original terrain data stored in the external memory device by the interpolation of weighted averaging method, and those formed mesh data are stored in internal memory device. Annular prism models around the station are assumed from newly-formed terrain mesh data stored in the internal memory by weighted averaging method, and annular prisms within 125 m from the station are assumed not only newly-formed mesh but also the station terrain data (the surface height of the ground or the water). At last, gravity values are calculated from annular prism models and summed up. Error of values of this terrain correction is expected to be within 2 mgals when KS-110 terrain data are used as the original terrain data for the terrain correction.View full abstractDownload PDF (1341K) -
Kenichi KAMIJO, Yoichiro FUJII, Shigeru AOKI1988 Volume 34 Issue 1 Pages 25-32
Published: June 25, 1988
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSUnified method of analysis for general linear model is proposed by using "Design of Observations" in which analysis of variance (ANOVA) is adopted. Observation system with several explanation variables is generally considered as a kind of function that is so-called black-box. We can only obtain observation data as output responses, when input conditions of the variables are given for the system. In this case, orthogonalarray can be applied assuming that each variable has two kinds of level for the system. If interaction effects among variables exist, we can easily detect them by F test in ANOVA. We can extend this principle and basic idea for more general systems in which we have many variables with many kinds of level.View full abstractDownload PDF (553K) -
Masaaki MURATA1988 Volume 34 Issue 1 Pages 33-57
Published: June 25, 1988
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSThis paper presents a summary of recent results of analyses of satellite laser ranging (SLR) data taken on LAGEOS (Laser Geodynamics Satellite) for the 3.3-year period from September 1983 to December 1986. LAGEOS data were analyzed to compute earth rotation parameters and a new global solution of the geocentric coordinates for 39 laser tracking stations. Laser station positioning was part of a simultaneous adjustment of parameters for LAGEOS orbital elements, an along-track acceleration, a solar radiation pressure coefficient in 30-day arcs and earth rotation parameters in 5-day subarcs. The earth rotation series computed in 5-day intervals have an internal precision of better than 2 mas for polar motion components and 0.15 ms for the change in the length of day. For 15 selected laser stations, baseline and station coordinate changes have been investigated by successive determination of station positions using annual datasets covering the 3-year period beginning in January 1984. It is shown that laser observed rates of change in baseline lengths are in general agreement with the motions predicted by the MINSTER-JORDAN AM1-2 model. Plate motions relative to Shimosato laser station have been observed for the first time using SLR data.View full abstractDownload PDF (2500K) -
- Comparison of Results Obtained through Simultaneous Observations with Two Gravimeters-Koichiro DOI, Hironori TSUKAMOTO, Mikio SATOMURA, Ichiro NAKAGAWA, Kaj ...1988 Volume 34 Issue 1 Pages 59-70
Published: June 25, 1988
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSContinuous observations of tidal variation of gravity were carried out at Shizuoka during the period of about 11 months from September 1984 to July 1985 by employing two LaCoste & Romberg gravimeters D-58 and G-680 installed side by side on the same concrete base. As effects caused by disturbed factors such as ambient temperature, atmospheric pressure and oceanic tides to the gravimeters installed on the same point are practically common, it is expected that their data will give similar results. In practice, however, δ-factors derived from the data of about 11 months by the gravimeter G-680 are slightly larger than those by the gravimeter D-58 for almost all tidal constituents, and their variations with time are not so similar. These causes are left unsolved at present. Comparing the δ-factors derived from about two-years' data, which were fully covered the period of the simultaneous observations with both gravimeters, by the gravimeter D-58 with those from about 11-months' data, both were in good agreement as well as about 0.1%. It was certainly found that the results derived from the data of about one year were fully stable and that those were reliable. For the purpose of earthquake prediction, the relation between the length of data and the difference of δA-factors obtained by both gravimeters was thoroughly examined. It was also shown by using the data of a duration longer than 30 days that the differ ences of the 5-factors were relatively stable, but that the amount of their fluctuations was considerably large.View full abstractDownload PDF (1107K) -
Naosuke SEKIGUCHI1988 Volume 34 Issue 1 Pages 71-74
Published: June 25, 1988
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSIn the previous paper (of the same title) [1], the method of calculation of the length of the Chandlerian period under the condition that the excitation should be the minimum, was mentioned. This condition is equivalent to the principle under which the component of the circular polarization in the motion of the excitation pole vanishes . When we can assume that the data of the polar motion are free from any effects of smoothing, and the errors in the data consist of only random ones, we can get the value of the length of the Chandlerian period, correcting the effects of the random noises. Thus the calculated value is found to be 415.9 mean solar days, . using the recent 6 years' data of the polar motion.View full abstractDownload PDF (284K) -
-Strain Response to Atmospheric Pressure Changes and Its Theoretical Estimation by the Boundary Element Method-Michio YANAGISAWA1988 Volume 34 Issue 1 Pages 75-84
Published: June 25, 1988
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSElastic constants (Young's modulus and Poisson's ratio) of rocks sampled from the tunnel of the Nokogiriyama Crustal Movement Observatory are measured by the statical method. The earth strain has been observed simultaneously by strain gages and extensometers in the tunnel of the Nokogiriyama Observatory during the period from January 1986 to March 1987. The data processing was made by the least square method. The strain response to atmospheric pressure changes is much affected by the topography over the observational tunnel. In order to explain this relationship theoretically, the auther applies the two-dimensional boundary element method to the topographic relief over the tunnel there. By comparing the calculated results with the ones observed by strain gages, we see that both the results show a good coincidence to each other.View full abstractDownload PDF (2059K) -
Karl-Rudolf KOCH1988 Volume 34 Issue 1 Pages 85
Published: June 25, 1988
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSDownload PDF (182K)
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