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Volume 32 (1986)
- Issue 4 Pages 227-
- Issue 3 Pages 167-
- Issue 2 Pages 89-
- Issue 1 Pages 1-
Volume 32, Issue 2
Displaying 1-8 of 8 articles from this issue
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Kazuki MIYAOKA, Hiroshi SATO1986 Volume 32 Issue 2 Pages 89-98
Published: August 25, 1986
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSA field experiment of the observation of crustal strains has been carried out on the base line (24 m) at the foot of Mount IWAKI, using Distometer, an instrument to measure small distance changes with invar wire. Accuracy of the observed strains at the first experiment wasDilatation =31.7.10-6Maximum shear strain= 5.0.10-6 Though these accuracies are not enough for the study of crustal deformation, ana lysis of data clarified that most of the error are resulted from the change in invar wire length due to rough handling during the measurement. Through the experiment, we found some points to improve in the measurement and get a confidence that the change in the maximum shear strain is observable with accuracy better than 2.10-6 with a caref ull treatment of the wire. Distometer provides us a way to observe strain changes quickly at the place where anomalous crustal activity are occured.View full abstractDownload PDF (3576K) -
-Proposal for Design of Observation in Geodetic Observations-Kenichi KAMUO, Yoichiro FUJII, Shjgeru AOKI1986 Volume 32 Issue 2 Pages 99-105
Published: August 25, 1986
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSDesign of observation iss proposed in this paper. This method is based on so-called Design of Experiments. It is very important for geodetic observations to obtain most reliable informations with minimum errors from geodetic data. Vectors of observation in observation vector space is projected onto orthogonal basic vector space, and we have two vectors, vector of error and vector of true observation. Parameters in each basic vectors can estimated independently, i.e. covariances between each parameters are all zeroes. We can easily estimate significant parameters by analysis of variances (ANOVA). Simple mathematical model can be constructed by these parameters and basic vectors.View full abstractDownload PDF (482K) -
-An Application do the Results of Precise Leveling between Kakegawa and Hamaoka-Kenichi KAMIJO, Yoichiro FUJII, Shigeru AOKI1986 Volume 32 Issue 2 Pages 106-112
Published: August 25, 1986
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSA unified method for analysing short time-series is proposed. When 16 points are given in a certain time-series, this method uses orthogonal array L16 whose columns correspond to discrete pulses. These pulses are discussed factors in design of experiments. We pick up several basic pulses which are orthogonal basic vectors, and other random pulses are assumed to be error pulses. ANOVA (Analysis of variance) is used in this method, and significant pulses are detected by F test (significant level is 5%). As an example, analysis for leveling data between Kakegawa and Hamaoka is tried by this method. The result shows that time change of height at Hamaoka relative to Kakegawa is superposition of secular and annual vertical crustal movement with con fidence level of 95%.View full abstractDownload PDF (652K) -
-Special Discussions on Detected High Strain Rates in the Oga and Senpoku District-Yoichiro FUJII, Kaname SUGITA, Katsumi NAKANE1986 Volume 32 Issue 2 Pages 113-124
Published: August 25, 1986
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSAs we had found the higher strain rates of the Oga and the Senpoku district as compared with the ones of the other district of Tohoku Japan in the second report of this series, more detailed analysis of strain was tried, and the results are given in thisthird report. The Oga district was resurveyed in 1940 after the Oga earthquake, and strain rate during 1940-1981 is deduced. The results are :0.32±0.06 microstrain/a in the north-west part0.08±0.06 microstrain/a in the south-east part.Therefore it can be concluded that the high strain rate was concentrated in the northwestpart of the Oga district. The Senpoku district was resurveyed in 1964/1970, 1973, and 1981. Then we can calculate the strain rate during some different periods. The highest was found in the north-west part of the Senopoku district during 1973-1981. The result is;1.73±0.57 microstrain/a. We have some examples of high strain rate 1-2 microstrain/a before occurrence of the earthquake that are possible pre-seismic abnormal strain rate as forerunner of the coming earthquake. The highest strain rate was detected in the Senpoku district nevertheless of the far distance from the source region of the 1983 Nihon-Kai-Chubu earthquake. The shorter time interval between two pre-seismic observational epochs may be able to enable us to detect high strain rate of pre-seismic crustal movement.View full abstractDownload PDF (1141K) -
Naosuke SEKIGUCHI1986 Volume 32 Issue 2 Pages 125-130
Published: August 25, 1986
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThe photometric observation around the region of the Bessel H of the Moon's surface was carried out on the occasion of the total lunar elipse of Oct. 18, 1985, using the multichannel polarimeter attached to the Cassegrain focus of the 91 cm reflector of the Dodaira Station of the Tokyo Astronomical Observatory. From the time of immersion to the Earth's umbra of the Bessel H, the effective optical radius of the Earth was determined. At the south geocentric latitude of 40°2, the optical effective boundary of the Earth is24 km±13 km (a priori S. D.)higher above the surface of the normal spheroid.View full abstractDownload PDF (633K) -
Yukio HAGIWARA, Michio YANAGISAWA, Shuhei OKUBO1986 Volume 32 Issue 2 Pages 131-139
Published: August 25, 1986
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSCrustal movements in the Boso peninsula are partially affected by the Pacific plate subduction along the Japan trench and partially affected by the Philippine-Sea plate horizontal motion along the Sagami trough transform faulting zone. The Nokogiriyama Crustal Movement Observatory located on the western coast of the Boso peninsula has continuously carried on watertube tiltmeter observations since its installation in 1959. We apply a trend analysis method called BAYSEA (Baysian seasonal adjustment program) to the tiltmeter data, and prove that maximum ground tilt toward the direction of NE-SW has an amplitude of 0.2 to 0.3 seconds of arc with a period of 2 to 2.5 years. We find that the Nokogiriyama ground tilt changes are not always consistent with wide-range crustal movements in the Boso peninsula, which are expected from levelling survey results repeatedly made by the Geographical Survey Institute. Migration of crustal movements, which was first reported by KASAHARA [2], has never been occurred after 1970 in comparison with tiltmeter data at the Aburatsubo Crustal Movement Ob servatory located about 20 km west of the Nokogiriyama station.View full abstractDownload PDF (899K) -
Fumiaki KIMATA1986 Volume 32 Issue 2 Pages 140-141
Published: August 25, 1986
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSDistance measurements using a Geodimeter 6BL and a Geodimeter 600 were made side-by side simultaneously to detect a possible bias between different-type Geodimeters. Interchange of their instrument positions, measurements were also made. Various measurements ranging 40m to 18 km showed that instrument bias is as small as 1±3 mm, which was less than the errors in distance measurements along the Awagatake Megami baseline.View full abstractDownload PDF (1805K) -
NATIONAL REPORT TO THE 12TH MEETING OF THE INTERNATIONAL GRAVITY COMMISSION TOULOUSE, SEPTEMBER 22-26, 1986THE NATIONAL COMMITTEE FOR GEODESY OF JAPAN, THE GEODETIC SOCIETY OF ...1986 Volume 32 Issue 2 Pages 147-166
Published: August 25, 1986
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThis document is the quadrennial report of gravimetric works made in Japan during the period from April 1982 to March 1986. It has been prepared to be submitted to the International Gravity Commission of the International Association of Geodesy at its 12th meeting held in Toulouse, France, from September 22 to 26, 1986. It summarizes gravi metric works such as international and domestic connections of gravity networks, absolute and relative gravity measurements, marine gravimetries, detection of gravity changes, geophysical interpretation of gravity data, theoretical researches of gravity field, etc. Complete references of the related articles are found in the bibliography towards the end of this report. The editor has compiled this report from the manuscripts submitted by Hokkaido University, the International Latitude Observatory of Mizusawa, Tohoku University, the Geographical Survey Institute, the Geological Survey of Japan, the Meteorological Research Institute, the Hydrographic Department of Japan, the National Institute of Polar Research, the Earthquake Research Institute and the Ocean Research Institute of the University of Tokyo, Shizuoka University, Nagoya University, Kanazawa University, Kyoto University and the Disaster Prevention Research Institute of Kyoto University.View full abstractDownload PDF (4266K)
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