測地学会誌
Online ISSN : 2185-517X
Print ISSN : 0038-0830
ISSN-L : 0038-0830
24 巻, 3 号
選択された号の論文の7件中1~7を表示しています
  • 関口 直甫
    1978 年 24 巻 3 号 p. 111-121
    発行日: 1978/11/25
    公開日: 2010/09/07
    ジャーナル フリー
     準日周章動項の励起の原因としては,大別して地球外套部及び核の総体に対して,それ以外の系から作用する摂動力によるものと,外套部と核との間に作用する摂動力によるものとの2種類に分けられる.しかし,後者は準日周章動項の他,チャンドラー周期極運動も同時に励起する作用があり,観測されるチャンドラー周期極運動と,準日周章動との振幅比を説明するためには,1日程度の短い時間尺度でおこる核の電磁現象を想定せねばならず,理論的に無理である.前者は準日周項の励起源としてはきわめて能率の悪い励起ではあるが,観測される準日周章動項の振幅を説明するためには充分である.
  • ―伸縮・傾斜変化に対するチェビシェフ近似関数の適用―
    石井 紘, 佐藤 俊也, 立花 憲司
    1978 年 24 巻 3 号 p. 122-131
    発行日: 1978/11/25
    公開日: 2010/09/07
    ジャーナル フリー
    Chebychev approximation function is employed for analyzing data observed by extensometers and water-tube tiltmeters. It is revealed that this method is very useful for the analysis of secular variation, because a small number of Chebychev coefficients can produce approximated observation data sufficient for analysis. It is shown that characteristics of secular crustal movement are easily investigated by filtering by the use of adequate Chebychev coefficients. As an example, this method is applied for the data obtained by extensometers and water-tube tiltmeters in Akita Geophysical Observatory.
  • 古沢 保, 竹本 修三, 尾上 謙介
    1978 年 24 巻 3 号 p. 132-140
    発行日: 1978/11/25
    公開日: 2010/09/07
    ジャーナル フリー
    The summary of distance measurements of six base-line networks in the western Japan, made with a Geodimeter model 6 since 1968, is presented. Precise measurements of three lines in a tunnel of the Amagase crustal deformation observatory were repeatedly made during 1970-1978. As a result of these measurements, strain accumulations exhibited the rates of (2.6-1.5)×10-6/year for the length of 400-1700 m. And the strain accumulation obtained from continuous records of a super-invar bar extensometer installed at the same turnnel exhibited the rate of 1.9×10-6/year for the length of 40 m. Both results are consistent within the observational error. At the Donzurubo and Wakayama networks, trend of strain accumulations obtained from electro-optical distance measurements are also consistent with those from continuous observations by extensometers.
  • 柳沢 道夫
    1978 年 24 巻 3 号 p. 141-152
    発行日: 1978/11/25
    公開日: 2010/09/07
    ジャーナル フリー
    The seiche obtained from tide gauge data in the Aburatsubo Tide Station has the period of 13.5-15.5 minutes and the amplitude of 85 mm. In order to confirm the Seiche theoretically, the author applies a Y-shaped one-dimensional model to Aburatsubo and Moroiso bays. The result shows that the free oscillation of sea-surface has the periods of 12.93, 7.18 and 4.82 minutes, respectively, corresponding to the fundamental, the second and the third harmonic waves, although the existence of higher harmonics is not confirmed from the observation. It is proved that the node of the second harmonic is near the tiltmeter station, and Koajiro bay seems ineffective on the seiche in Aburatsubo bay. Tiltmeter observations indicate that the effects of the seiche have E-W and N-S tilt components amounting to 2.35×10-3 and 9.43×10-3 second of arc, respectively. On the other hand, the tilting amplitudes by the seiche are theoretically estimated to be 2.95×10-3 and 3.21×10-3 second of arc, respectively. The calculated result shows a good coincidence with the E-W component observed but it becomes about a third of the observed value for the N-S component.
  • 梅田 康弘, 山崎 純一
    1978 年 24 巻 3 号 p. 153-162
    発行日: 1978/11/25
    公開日: 2010/09/07
    ジャーナル フリー
    Since 1972, the crustal deformation has been observed by use of silica tube exten someters, water-tube and horizontal pendulum tiltmeters at Abuyama Seismological Observatory. The principal axis of compressional strain obtained seismologically and geodesicallylies in approximately E-W direction, but the observation of secular strain in our vault indicates the extension in E-W direction. This contradiction may be explained as follows. The fold with NS axis is advanced by the compresnional force in E-W direction and the hanging wall of fracture zone (N20?KE strike; dip angle of 20?KW) at the local antiform slides down to the west side. Thus, the progress of shear fold results in the extension in E-W direction. Some of instruments are set across a fracture zone about 1 m thick. The thickness of this fracture zone with left lateral slide component is increased by precipitation and decreased by discharge of water. The discharge from observation, vault increased abruptly mid-1975 and 1976. The variations of discharge, strain and tilt are compared with the weekly count of micro-earthquakes, assuming the seismicity may represent the stress change in wider area. But the correlation between them is vague.
  • 柳沢 道夫, 島田 誠一, 佐藤 忠弘, 坪川 恒也, 佐藤 範雄, 田中 豊, 加藤 正昭
    1978 年 24 巻 3 号 p. 163-171
    発行日: 1978/11/25
    公開日: 2010/09/07
    ジャーナル フリー
    Simultaneous observations of earth tides were carried out by tiltmeters of three types at the Aburatsubo and the Nokogiriyama Crustal Movement Observatories during the period from December 1977 to March 1978 for the purpose of comparing the characteristics of these tiltmeters. The tiltmeters used in these observations were V-M horizontal pendulums, Super-Inver horizontal pendulums and TEM tiltmeters. A third of the observed records was analysed by the Method of International Center of Earth Tides. The preliminary results are compiled in Table II.
  • 田島 広一, 井筒屋 貞勝, 吉村 愛一郎, 太島 和雄, 大島 弘光
    1978 年 24 巻 3 号 p. 172-177
    発行日: 1978/11/25
    公開日: 2010/09/07
    ジャーナル フリー
    The tidal gravimetrrc observations were carried out by means of three LaCoste and Romberg gravimeters at the Aburatsubo and the Nokogiriyama Observatories during the period of about three months from December 1977 to March 1978. The tidal factors were obtained as 1.24 to 1.42 for the main tidal components, that is O1, K1, M1 and S1, from the observed data.
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