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Volume 33 (1987)
- Issue 4 Pages 299-
- Issue 3 Pages 171-
- Issue 2 Pages 89-
- Issue 1 Pages 1-
Volume 33, Issue 4
Displaying 1-13 of 13 articles from this issue
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Tamotsu FURUZAWA, Fumio OHYA, Masahiro TERAISHI1987 Volume 33 Issue 4 Pages 299-306
Published: March 25, 1988
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSAt the Miyazaki Crustal Movement Observatory, data acquisition and analysis for observation network of crustal activities are executed on multi-computers system. This data processing system is operated with a view to detect the phenomena related to the occurrence of earthquakes at Hyuganada. Analysis of data by extensometers at the Miyazaki observatory reveals an abnormal extension in E3 component 6 hours before the occurrence of the earthquake on March 18, 1987 (M=6.6). It is also suggested that the earth tides in E3 data are magnified slightly after rainfalls.View full abstractDownload PDF (841K) -
-Test for Vertical Crustal Movement at Minami-Izu and Okada in Relation to the 1986 Izu-Oshima Eruption-Kenichi KAMIJO, Yoichiro FUJII, Shigeru AOKI1987 Volume 33 Issue 4 Pages 307-313
Published: March 25, 1988
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSA method of estimation for sea level change in a time-series of mean sea level is proposed. When continuous 32 points are given in it and they have an increasing or decreasing trend, we can easily estimate the sea level difference between both ends of the term by this estimation method, in which pulse-decomposition method is adopted. As an example, the analysis of mean sea level at Minami-Izu and Okada is tried by this estimation method, because we are interested in the vertical crustal movement in relation to the 1986 Izu-Oshima Eruption. The real sea level changes between both ends of the terms are estimated with 95% confidence interval for abnormal upheaval of the earth crust.View full abstractDownload PDF (468K) -
Yukio HAGIWARA1987 Volume 33 Issue 4 Pages 315-320
Published: March 25, 1988
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSSuppose gravity anomaly on a double-layer structure consisting of surface layer and underlying bedrock. We assume density contrast between them and mean depth to their boundary, and then we can calculate subsurface topography of the boundary by using, for example, Fourier series method or Fourier integral method. In these methods, elevation of the subsurface topography from the mean depth is assumed to be so small, that the second and higher powers of the elevation can be usually neglected. In some actual cases, such a neglect can not be correct. We propose in this paper a simple method for obtaining the subsurface topography without neglecting the second and higher powers of the elevation. The actual calculation result is shown in a figure.View full abstractDownload PDF (560K) -
Yoshiko KOTAKE, Yukio HAGIWARA1987 Volume 33 Issue 4 Pages 321-328
Published: March 25, 1988
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSTerrain correction of the Bouguer anomaly is usually computed by neglecting topo graphy in zones distant from a measuring point. Such a neglect may result in truncation errors for Bouguer anomaly calculations. We estimate the truncation errors and their vertical gradients by using the worldwide elevation and bathymetric data set with a grid spacing of 5-min, latitude by 5-min. longitude, which was recently published by the National Geophysical Data Center, NOAA. The truncation error amounting to 150 mgal on Japan islands is caused presumably by the bathymetric topography of the Pacific Ocean.View full abstractDownload PDF (759K) -
-Deformation of the Concrete Floor of the Observation Tunnel-Tsuneo YAMAUCHI1987 Volume 33 Issue 4 Pages 329-336
Published: March 25, 1988
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSContinuous observations of crustal deformations by extensometers which have many detectors have been carried out at the Mikawa Crustal Movement Observatory since October 1978. In this paper, a detailed comparison of strain changes observed with detectors on the basement rock and on the concrete floor is mainly described. It was found that there was a good coincidence between them over the whole period from the tidal variation to the secular change. It seems that the crustal deformations by extensometers are hardly affected by the deformation of the cement itself.View full abstractDownload PDF (746K) -
Kosuke HEKI1987 Volume 33 Issue 4 Pages 337-345
Published: March 25, 1988
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSThe final stage of the geodetic VLBI data analysis is the adjustment of various "stationary" parameters such as station positions and additional "non-stationary" para meters such as the inter-station offsets of atomic clocks and atmospheric zenith path delays. With the conventional least-squares estimation method, complicated techniques have been needed to estimate the parameters with temporal variation. For example, the variation of clock offsets is usually assumed to be represented by a set of para bolic curves connected by several discontinuities. With a new parameter estimation method based on Kalman filtering technique, both the deterministic estimation of stationary parameters and the tracking of the values of non-stationary parameters varying according to some stochastic process are possible. This enables the VLBI parameter estimation without operator-dependent procedures to modelize such temporal variations. It is also shown that the higher repeatability of the baseline lengths is obtained by Kalman filter method than by the conventional least-squares method.View full abstractDownload PDF (964K) -
Noboru INOUCHI, Taketsune HOSONO1987 Volume 33 Issue 4 Pages 347-359
Published: March 25, 1988
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSFrom the precise levelling survey along the route connecting Kakegawa to Omaezaki, it is clear that there exists the yearly change of the ground movement at Hamaoka near Omaezaki, whose pattern indicates the subsidence in winter and the reverse in summer. Some source mechanisms have been presented to interpret the phenomenon, however they are not su licient enough to express both the magnitude and phase of the yearly change curve. A new idea is brought forward from the study of the precise levelling results and the tiltmeter records observed at Omaezaki. On the tiltmeter record the difference between day time (10 AM-4 PM) mean value and daily mean value is not always constant through the year and it takes the distri bution pattern such as maximum value in July and minimum in December. It is deduced that the crustal movement revealed by the tiltmeter exists also in the levelling results because the levelling survey is usually performed in the day time. Consideration is given on the tidal load effect and further on the tidal potential theory.View full abstractDownload PDF (1026K) -
IAG Section I PositioningMasao ISHIHARA1987 Volume 33 Issue 4 Pages 361-363
Published: March 25, 1988
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESS -
Atsushi TSUCHIYA, Takashi SAITO1987 Volume 33 Issue 4 Pages 364-366
Published: March 25, 1988
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSDownload PDF (347K) -
Shuhei OKUBO, Yoichi FUKUDA1987 Volume 33 Issue 4 Pages 367-368
Published: March 25, 1988
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSDownload PDF (183K) -
Masa-Katsu FUJIMOTO1987 Volume 33 Issue 4 Pages 369-370
Published: March 25, 1988
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSDownload PDF (174K) -
Masatsugu OOE1987 Volume 33 Issue 4 Pages 371-372
Published: March 25, 1988
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSDownload PDF (238K) -
Koichi YOKOYAMA1987 Volume 33 Issue 4 Pages 373-376
Published: March 25, 1988
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSDownload PDF (393K)
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