巻号一覧
17 巻 (1971)
- 4 号 p. 139-
- 3 号 p. 85-
- 1-2 号 p. 1-
17 巻, 4 号
選択された号の論文の8件中1～8を表示しています
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山口 生知1971 年 17 巻 4 号 p. 139-143
発行日: 1972/08/02
公開日: 2011/07/05
ジャーナル フリー1937年から1958年までの22年間におけるDataについて調べてみた. 目的は日本における大地震のとき,または1941年のLisbon地震のときのように地震前に平均海水面の著しい変化があるかどちかを調べることであつた.海水温度等のDataがないのでLisbonのときと同様に22年間の各月に対する平均を計算してその年変化曲線をつくつた.(Fig.1.).この曲線の模様は日本やLisbonなど北半球のものとは異なつて,むしろ南半球のものと似ているのは不可解である.この曲線からのdeviation, ΔL'をとつて12ヵ月の平均を年平均値とした,この値のprobable error,εを計算してみると,ε=±5.8mmとなつた.それ故に一次近似としては海水密度,気圧その他の影響はとれているものと考えられる. つぎに,この永年変化曲線(Fig.2)の上に大地震の起つた年を書き入れてみると,1943年のM=7.6, d=600kmという地震前には連続した著しい変化を見たがその他の場合には左程著しくはないが1943年から1957年までの15年間に7つという大地震が頻繁に起つているので年平均海水面もそれに応じて頻繁に変化しているのが見られる. 最後に日本の場合と同様に大地震の12ケ月前と6ケ月後の月平均海水面変化を調べてみたが,日本の場合の約100個の地震に対して僅かに7ケであったが,日本の場合と同様に大地震の5ケ月前に極大,2ケ月前に極小という結果を得たことは面白いと思う.(Bull. Earthq. Res. Inst.38,1960参照).このときの平均誤差は±(12～20)mmであるが地震の起つた月の値を参考までにあげると, ΔL'=(64±13)mmである.(Fig.4).抄録全体を表示PDF形式でダウンロード (403K) -
萩原 幸男1971 年 17 巻 4 号 p. 144-152
発行日: 1972/08/02
公開日: 2011/03/01
ジャーナル フリーThe author makes an attempt to establish a one-to-one mathematical relationship between the gravity field and the mantle convection currents in two-dimensional models. It is presumed that an up-coming convective flow produces a high gravity anomaly, on the other hand a low anomaly is caused by a down-going flow. The set of differential equations governing the steady-state convective motion is solved to obtain the density disturbances and the corresponding streamlines. Applying the solution to the satellite gravity anomaly, the author discusses the convective flow supposed to go down along the Japan Arc.抄録全体を表示PDF形式でダウンロード (783K) -
長沢 工1971 年 17 巻 4 号 p. 153-159
発行日: 1972/08/02
公開日: 2011/03/01
ジャーナル フリーThe simultaneous observation of artificial satellites is one of the most powerful means for connecting the distant geodetic datum stations or the triangulation nets. Through these observations, the direction and distance between two stations are first determined and then world-wide frame work connecting all the observation points is constructed. In these work, large quantity of the observational data which is not always coincident one another must be dealt with, and some adjustment is necessary. In this adjustment, three dimensional consideration is required because the observation stations are distributed globally and it is impossible to apply the two dimensional model to these stations. In this paper, the writer treats a method of the three dimensional adjustment. This method corresponds essentially to solve the observational equations applying the method of least square and this is equally applicable for the data of direction observation and of range measurement of the satellites. This adjustment will be useful for the determination of accurate posion of Japanese datum referred to other datum points and the construction of large triangulation net including the long base lines in Japan.抄録全体を表示PDF形式でダウンロード (666K) -
柳沢 道夫1971 年 17 巻 4 号 p. 160-169
発行日: 1972/08/02
公開日: 2011/07/05
ジャーナル フリーThe general description of the TEM tiltmeter has been already presented [1]. In the present paper, details of the electronic devices of the instrument is introduced, which consist of the following four sections, 1) differential transformer as a transducer, 2) exciter of the differential transformer and amplifie, 3) power-supply and4) recorder and reset circuit, The author's intention of designing the electronic devices is as follows:1) The life time should be as long as possible.2) Electronic parts should be easily obtained at the market.3) Repairing time should be as short as possible. It has beea cleared that MTBF (mean time between failures) of the present electronic circuits, shown on the Weibull distribution paper, is only 4 years.抄録全体を表示PDF形式でダウンロード (7520K) -
山田 重平1971 年 17 巻 4 号 p. 170-177
発行日: 1972/08/02
公開日: 2011/03/01
ジャーナル フリーWater-tube tiltmeter observations have been conducted at the Aburatsubo Crustal Movement Observatory since 1949. The present paper reviews the data accumulated in the past twenty years in order to examine if the station observation of this type can monitor the crustal movements satisfactorily or not. The Miura Peninsula area, in which the Aburatsubo station is located, is particularly suitable for this purpose, because the G. S. I's data of frequent relevelling and of mareographic observation are available for comparison. Following are the conclusions thus obtained: (i) Gradual westward tilting of the ground, which was recorded at Aburatsubo for the peiriod 1949-1960, turn to active eastward tilting about 1961. The basic mode of this movements, particularly the active eastward tilting since 1961, is witnessed by the levellings in the southern part of the peninsula. Similar mode of land movements is also noticed on the mareographic records at Aburatsubo and Mera as well as on the tiltmeter record at Nokogiriyama, where the latter two stations are located at an adjacent peninsula. (ii) As to the detailed features, however, tiltmeter data do not agree with the geoditic data necessarily. The writer can hardly explain the causes of disagreement, but he tenta-tively considers that it might be attributed partly to sea level anomalies which result in local tilting of the coastal ground by loading.抄録全体を表示PDF形式でダウンロード (714K) -
佐藤 裕, 市原 満1971 年 17 巻 4 号 p. 178-186
発行日: 1972/08/02
公開日: 2011/03/01
ジャーナル フリーIn relation to the research of the present crustal movemont in the South Kanto District, the records of the retriangulation made soon after the Great Kanto Earthquake of 1923 have been reanalized. The horizontal movement derived by the present analysis is well accordant with other observed facts, such as the vertical movement discovered by the re-leveling. The crustal movement associated with the earthquake is estimated to have resulted from a shallow dip thrust faulting with large lateral slip. From the amount of the horizontal displacement near the fault plain, the dip of the fault is estimated as 25°-40° in NE direction. The strain change of the earth's crust at the time of the earthquake shows that the crust in the source region had been compressed toward north-south before that time.抄録全体を表示PDF形式でダウンロード (876K) -
田島 広一, 井筒屋 貞勝1971 年 17 巻 4 号 p. 187-190
発行日: 1972/08/02
公開日: 2011/03/01
ジャーナル フリーMeasurements of vertical gradient of gravity carried out at Keio Plaza Hotel Building which was built recently. This building is in Tokyo (latitude: 35°41.2'E longitude: 139°41.9'N) and its height is about 170 m above the ground. The mean value of the gradient measured was 0.3049 mgal/m ± 0.00032SD. There are four stations where the vertical gradients of gravity have been measured in and around Tokyo. The distribution has a tendency to increase toward north in this area same as the free air anomaly distribution.抄録全体を表示PDF形式でダウンロード (358K) -
檀原 毅1971 年 17 巻 4 号 p. 191-194
発行日: 1972/08/02
公開日: 2011/07/05
ジャーナル フリーPDF形式でダウンロード (496K)
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