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Volume 30 (1984)
- Issue 4 Pages 249-
- Issue 3 Pages 169-
- Issue 2 Pages 75-
- Issue 1 Pages 1-
Volume 30, Issue 1
Displaying 1-8 of 8 articles from this issue
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Yukio HAGIWARA1984 Volume 30 Issue 1 Pages 1-16
Published: May 25, 1984
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSFitlering techniques separate a gravity map into short- and long-wavelength ones. It can be concluded on the basis of gravity and topography data that terrain masses of wavelength shorter than 160 km are sustained by an elastic strength of the crust but those of longer wavelength are balanced in an isostatic equilibrium with the crustal thickness. In this paper, we use a two-dimensional Box-car window as a low-pass filter with its application to gravity zoning of the Japan island-arcs. We see a clearcut zone arrangement of positive and negative gravity anomalies along the island-arcs.View full abstractDownload PDF (5852K) -
Gen-ichiro HORI1984 Volume 30 Issue 1 Pages 17-28
Published: May 25, 1984
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSA probe is connected to the base satellite by a long cord, and released to investigate nearby space around the satellite. In such a project it is important to know the probe's motion relative to the satellite. The relative motion is either a relative Keplerian type or a pendulum type. In general these two types of motion alternate. When the satellite revolves the earth in 2 hours and a probe of 100 kg is released as long as 10 km, the tensile force of the cord is about 700 gw.View full abstractDownload PDF (739K) -
Minoru SASAKI1984 Volume 30 Issue 1 Pages 29-40
Published: May 25, 1984
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSA satellite laser ranging system was installed at the Simosato Hydrographic Obser vatory. The system equips an receiving telescope of 60 cm diameter and a laser subsystem which transmits pulses of 150 mJ energy per pulse with 200 ps width in a repetition rate of 4 pps. The range observations to Lageos, Starlette and Beacon-C have been continued since March 1982. The total numbers of returns obtained by the end of January 1984 are 44, 828 from 201 passes of Lageos, 35, 757 from 161 passes of Starlette and 111, 364 from 287 passes of Beacon-C. The mean range accuracy per one return for these satellites is around 10 cm. To obtain much range data and to attain better precision for range residual some testings and improvements have been made. The geocentric coordinate of the ranging system at the Simosato Hydrographic Observatory is estimated by an orbital processor developed using range data obtained at the observatory and other laser sites in the world. The geocentric coordinate of the intersecting point of azimuth and elevation axes of the laser ranging system is obtained on the basis of LPM 81.12 coordinate system which has been used as the basic coordinate to estimate earth rotation parameters at the University of Texas . The preliminary result is 33° 34′ 39″.683N, 135° 56′ 13″.156E and 100.90 meters (height from a reference ellipsoid: A=6378137m and 1/f=298.257). The comparison of the result with the geodetic coordinate surveyed in the Tokyo Datum derives the datum shift correction from the Toko Datum to the LPM 81.12 system as ΔU= -142 .8 m, ΔV= +510.7 m andΔW=+681.0 m. According to the results obtained by the lunar laser ranging, an eastward rotation of the LPM 81.12 system of 0″.197 makes the same longitude for the reference point of the 2.7 m telescope at the McDonald Observatory as obtained by the lunar laser ranging. If it is applied to the longitude of Simosato site, the datum shift correction changes to ΔU=-146.3m, ΔV= +507.1 m and ΔW = +681.0 m and the Tokyo Datum is to be combined with the astonomical geocentric coordinate system almost close to the BIH system.View full abstractDownload PDF (1580K) -
Mitsumi FUJISHITA1984 Volume 30 Issue 1 Pages 41-49
Published: May 25, 1984
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSTime variations of relative positions of celestial radio sources are investigated to estimate errors on group delay observations for geodesy and geophysics with a very long baseline interferometer. Differences of relative positions of 0355+508, 1226+023 and 1641+399 are studied among catalogues of G. H. Purcell Jr. et al. (1980), J. L. Franselow et al. (1981) and S. Ye (1982). It seems that systematic errors exist between the second and the third catalogues. There is no time variation exceeding 30 milli-arc-second between mean observation epoch 1975 and 1981.View full abstractDownload PDF (602K) -
Shoji SAKATA, Seiichi SHIMADA1984 Volume 30 Issue 1 Pages 50-58
Published: May 25, 1984
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSWe have been developing an ocean bottom tiltmeter applicable to continuous tilt observation in the ocean area. In the former paper [1], the purpose of the development, the concept of the design, the structure and the character of tiltsensors were described. In this paper we deal with the latter part of development. After we successfully carried out the long term stability test of tiltsensors combined with the attitude control apparatus, the underwater part was finally assembled and the final long term stability test was done in the vault of Tateyama Observatory (GSI) to reveal no problem. Then the tiltmeter was installed on the free surface of the sea bottom of 20m depth off Hiratsuka in Sagami Bay. Observation showed that the drift rate is very high especially at the time of stormy weather. Since the original purpose of the experiment was to determine whether or not it is possible to carry out tilt observation in and on a sand layer, we decided to bury the tiltmeter in the sand layer in order to avoid wave effects. In October 1982 the tiltmeter was removed 10m to the south from the previous location and was buried at 2-3m depth. To get better coupling with the sand layer of high N-value, a four-foot steel platform was adopted under the tiltmeter. After burial, the drift rate decreased rapidly to a present mean value of about 5μrad/month. Thus, we conclude that it is possible to detect short term tilt change of the order of 1μrad by an ocean bottom tiltmeter in a sand layer.View full abstractDownload PDF (1512K) -
Fumiaki KIMATA1984 Volume 30 Issue 1 Pages 59-60
Published: May 25, 1984
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSMeteorological corrections for electro-optical distance measurements can be made out accurately when temperature lapse rate in planetary boundary layer near the ground surface becomes very small. This letter discusses the diurnal variations of temperature lapse rate by making use of data from Meteorological Research Institute. The lapse rate is analyzed from the monthly mean of atmospheric temperatures at altitudes from 10 m to 200 m above the ground. The duration when the rate is within ±0.25°C/100 m amounts to seven hours around sunset in summer but only one hour in winter. The rate changes very quickly in the morning. The maximum rate appears just at the time of sunrise and becomes very small a few hours after sunrise.View full abstractDownload PDF (358K) -
Joenil KAHAR1984 Volume 30 Issue 1 Pages 61-68
Published: May 25, 1984
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSPrimary triangulation network of Jawa was started in 1862 and completed in 1880. This network was computed in a system which was called Genuk System. This network was extended to Sumatera and Nusa Tenggara Isles and the computation in the Genuk System for those area was started in 1931. Beside this system there were two other systems, Malayan System for Bangka, Riau & Lingga and Serindung System for West Kalimantan. A unified datum was established after a Doppler satellite observation held in Padang, and the datum was called the Indonesian Datum 1974 (ID-1974). Determination of geoid in the Indonesian Archipelago was worked out by combining a global detailed gravimetric geoid computed by March & Chang (1976) and the oceanic geoid derived from GEOS-3 altimetry data (Rapp, 1979). A new precise leveling network in Jawa has been designed and measured since 1980. The measurements of this network will be completed in 1985, so that the measurements may be continued to Sumatera. Principal gravity base stations were established through a joint working between the Geological Survey of Indonesia and the University of New England, Australia.View full abstractDownload PDF (691K) -
[in Japanese]1984 Volume 30 Issue 1 Pages 69-70
Published: May 25, 1984
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSDownload PDF (287K)
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