測地学会誌
Online ISSN : 2185-517X
Print ISSN : 0038-0830
ISSN-L : 0038-0830
32 巻, 2 号
選択された号の論文の8件中1~8を表示しています
  • 宮岡 一樹, 佐藤 裕
    1986 年 32 巻 2 号 p. 89-98
    発行日: 1986/08/25
    公開日: 2010/09/07
    ジャーナル フリー
    A 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.
  • ―観測計画法の提案―
    上條 賢一, 藤井 陽一郎, 青木 滋
    1986 年 32 巻 2 号 p. 99-105
    発行日: 1986/08/25
    公開日: 2010/09/07
    ジャーナル フリー
    Design 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.
  • ―掛川~浜岡間を例として―
    上條 賢一, 藤井 陽一郎, 青木 滋
    1986 年 32 巻 2 号 p. 106-112
    発行日: 1986/08/25
    公開日: 2010/09/07
    ジャーナル フリー
    A 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%.
  • ―男鹿および仙北地域に関する特論―
    藤井 陽一郎, 杉田 要, 中根 勝見
    1986 年 32 巻 2 号 p. 113-124
    発行日: 1986/08/25
    公開日: 2010/09/07
    ジャーナル フリー
    As 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.
  • 関口 直甫
    1986 年 32 巻 2 号 p. 125-130
    発行日: 1986/08/25
    公開日: 2010/09/07
    ジャーナル フリー
    The 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.
  • 萩原 幸男, 柳沢 道夫, 大久 保修平
    1986 年 32 巻 2 号 p. 131-139
    発行日: 1986/08/25
    公開日: 2010/09/07
    ジャーナル フリー
    Crustal 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.
  • 木股 文昭
    1986 年 32 巻 2 号 p. 140-141
    発行日: 1986/08/25
    公開日: 2010/09/07
    ジャーナル フリー
    Distance 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.
  • NATIONAL REPORT TO THE 12TH MEETING OF THE INTERNATIONAL GRAVITY COMMISSION TOULOUSE, SEPTEMBER 22-26, 1986
    THE NATIONAL COMMITTEE FOR GEODESY OF JAPAN, THE GEODETIC SOCIETY OF ...
    1986 年 32 巻 2 号 p. 147-166
    発行日: 1986/08/25
    公開日: 2010/09/07
    ジャーナル フリー
    This 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.
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