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Volume 26 (1980)
- Issue 4 Pages 227-
- Issue 3 Pages 137-
- Issue 2 Pages 75-
- Issue 1 Pages 1-
Volume 26, Issue 3
Displaying 1-6 of 6 articles from this issue
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Ichiro MURATA1980 Volume 26 Issue 3 Pages 137-146
Published: November 30, 1980
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSEffects of electric and magnetic fields on free fall methods of gravity measurements are investigated. The effects of Coulomb forces are calculated in the following way. Some amounts of electrostatic charges are induced on a falling object due to a stray capacity and a contact potential difference between the falling body and the vacumm chamber. The falling object drops carrying the induced electrostatic charges with itself. The Coulomb force is calculated, which is exerted between the falling object and the vacuum chamber on the assumption that the falling object is a point charge and the shape of the vacuum chamber is cylindrical. The overall effect of the Coulomb force to the measured gravity during a single drop is next estimated. The result shows that the effect reaches micro Gal level and cannot be neglected in a precise gravity measurement. Magnetic effects, on the other hand, is found to be negligible in usual case.View full abstractDownload PDF (668K) -
Takehisa HARADA1980 Volume 26 Issue 3 Pages 147-171
Published: November 30, 1980
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSFourteen years have elapsed since the first paper on the Universal Program for adjusting strictly any geodetic network, which consists of four kinds of observations suchas side length, azimuth, angle and direction, was presented in the Bulletin of the Geographical Survey Institute, Japan (vol. 12, 1966). The program had been frequently improved according to the development of computer and the advancement of science. Im-portant improvements had been reported in the Journals of the Geodetic Society of Japan every time they were added to the program. There are, however, some important remarks which have not been mentioned in these papers. Nowadays, the improvement of the program seems to be sluggish. Under these circumstances reviewing total flow of the program including these remarks will be useful for persons using the program or considering introduction of the program.View full abstractDownload PDF (2147K) -
Hiromi FUJIMOTO, Chuichi KAKUTA, Yasuhiro GANEKO1980 Volume 26 Issue 3 Pages 172-179
Published: November 30, 1980
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSAccuracy of Doppler positioning given by a shipboard NNSS receiver is examined in comparison with results obtained by use of a NNSS receiver for geodetic use. When the broadcast ephemeris is used, little difference is recognized between these two receivers, as far as the ship stays at a pier. It is experimentally obtained that 0.20.3 nautical mile of position fix error results from each knot of unknown ship's velocity. Usually the ship's position is determined within an accuracy of 0.20.3 nautical mile by NNSS. In some cases the shipboard receiver gives errors more than ten times larger than usual errors. However, the origin is not certain.View full abstractDownload PDF (930K) -
-Stability of Hagiwara's Formula and Asymptotic Formula-Masanori SAITO1980 Volume 26 Issue 3 Pages 180-186
Published: November 30, 1980
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSErrors in the geoidal heights computed by a truncated Stokes integral are evaluated in terms of Molodenskii truncation error coefficients Qn and the harmonic component of gravity anomalies. Hagiwara derived a convenient set of equations for the numerical computation of Qn. In this paper numerical stability of Hagiwara's recurrence formula is analized based on a simplified assumption on the stochastic properties of rounding error. It is found that the formula is unstable in that the error variance increases with n3. A simple asymptotic formula is derived for the computation of high degree trunca tion error coefficients. The formula is similar in form to the formula proposed by Ganeko.View full abstractDownload PDF (538K) -
Michio YANAGISAWA1980 Volume 26 Issue 3 Pages 187-199
Published: November 30, 1980
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSThe purpose of the present study is to clarify the precipitation effects on crustal tilt at the Usami observation site, the northern part of the Izu Peninsula. The measure ments have been carried out by using two sets of TEM-tiltmeter since July 1979. There is a small fault across the observation vault, and the tiltmeters are established on both the sides of the fault. The observed results of tilt are so much affected by rainfall, that the method using a linear transfer function is applied to the observed results to cancel out the rainfall effects. It is proved that the transfer function is well consistent with the tank model procedure. The transfer function method is applied to the tilt data obtained before and after an earthquake of M 6.7 occurred nearby the observation site. The pre- and coseismic tilt changes are clarified by the prediction using the transfer function.View full abstractDownload PDF (1206K) -
Minoru TANAKA1980 Volume 26 Issue 3 Pages 200-217
Published: November 30, 1980
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSSecular variations of the geomagnetic total field difference (hence force GTFD) of Mizusawa-Kakioka were detected using the proton data with 0, 1 nT observation sensitivity over a period of about 11 years of sunspot cycle from Apr . 1969 to Jun. 1980 through the following external field elimination methods; (1) Kp index-sunspot numbers method (2) External field enm elimination method. From the analysis based on (1), a biennial oscillation which seems to be due to an effect of sunspot solar cycle was detected in the secular variation of GTFD after elimination of the 11 year sunspot cycle. It was found that the phase pattern of the secular trend of GTFD excepting the biennial oscillation shows the minimum phase near 1974, which is observed in the secular variation of the vertical field difference . Generally speaking, in the secular variation of GTFD, annual, biennial and irregular oscillations can be found, which seem to be related to the periodic change in the formation of magnetosphere produced between summer and winter solstices, the solar cycle effect excepting 11 year sunspot cycle and those coupling effects or tectonomagnetic effect, respectively. From the analysis based on (2) to investigate the above results, the phenomena which seem to be due to an effect of tectonomagnetism were detected in the duration period from 1976 to Jun. 1980, comparing with the strain data of Sanriku and Tateyama Crustal Observatories. It was found that the crustal motion seems to precede the secular variation of GTFD about 1.5 month. As a conclusion, it is suggested that the secular variation of GTFD of Mizusawa-Kakioka may be able to interprete mostly as the result of tectonomagnetic effect due to the compression from the Pacific plate . The origin of the change of fine structure is still uncertain, though the change in speed gradient of the macroscopic secular variation of GTFD and the frequency modulation are seen barely from near the latter half of 1974.View full abstractDownload PDF (1709K)
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