巻号一覧
16 巻 (1970 - 1971)
- 4 号 p. 177-
- 3 号 p. 99-
- 1-2 号 p. 1-
16 巻, 4 号
選択された号の論文の9件中1～9を表示しています
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志知 龍一, 松浦 宏, 飯田 汲事1971 年 16 巻 4 号 p. 177-189
発行日: 1971/08/25
公開日: 2011/07/05
ジャーナル フリーThis paper is the progress report concerning with the continuous observation of crustal deformation at Inuyama. The records used for the analysis are of the extenso meter and water tube tiltmeter, the recording periods of which are 20 months and 34 months respectively. The crustal deformation at Inuyama was revealed by the present analytical results. The direction of the principal strain of extension was found to be from N 45°KE to N 80°KE and is nearly concordant with the strike of geologic structure. Further the direction of principal strain of contraction was estimated from N 10?KW to N 45°KW and is concordant with that of the dip of the geologic strata. Maximum shearing stress was obtained as 0.6×10-6 per year. Maximum dip was mentained at a constant rate of 0.8×10-6/year, the direction of which was downwards N 40°KW. The strain with short period was found to be different from the general crustal deformation and was infered to be caused by the change in the pressure of water filled in the pore in rocks beneath the ground. The southeastern upheaved region along the Neo valley earthquake fault generated by the Mino-Owari earthquake of 1891 shows a tendency to subside in recovery movement and the strain accumulation was inferred to be going on with the strain rate less than 1×10-6/year.抄録全体を表示PDF形式でダウンロード (3110K) -
萩原 幸男1971 年 16 巻 4 号 p. 190-198
発行日: 1971/08/25
公開日: 2010/09/07
ジャーナル フリーThe author estimates the truncation errors in the Stokes formula integration at the Tokyo datum station, using Kaula's [9] spherical coefficients of geopotential. These errors are obtained at every ten degrees of truncation angle. The results indicate that the truncation errors with regard to η=2 and 3 orders of spherical coefficients are not negligible small. The author also suggests that it is difficult to determine the geoid from the locally obiained gravity anomaly in combination with the anomaly measured by satellite orbit analyses.抄録全体を表示PDF形式でダウンロード (784K) -
田島 広一1971 年 16 巻 4 号 p. 199-201
発行日: 1971/08/25
公開日: 2010/09/07
ジャーナル フリーThe drift correction often comes into question when gravity measurements are made by use of a spiral spring-type gravity meter. In this paper, the drift data of the LaCoste and Romberg gravity meter G 34 of the Earthquake Research Institute, Tokyo University, is discussed. The writer has observed drift once a day for about eight years since this gravity meter was purchased in 1963. The drift data show evidently annual changes, the amplitude of which exceeds 1 mgal. The drift-rate is large in the winter season but small in the summer. The correlation coefficient between the drift-rate and room tem perature is -0.82. On the other hand, the new type LaCoste and Romberg gravity meter G 210 equipped with continuous temperature control mechanism was purchased on September 1969. The drift-rate of G 210 seems relatively small as compared with that of G 34.抄録全体を表示PDF形式でダウンロード (326K) -
山内 常生, 志知 龍一, 飯田 汲事1971 年 16 巻 4 号 p. 202-208
発行日: 1971/08/25
公開日: 2011/07/05
ジャーナル フリーThe noise strain associated with precipitation has been eliminated from the strainmeter record of crustal deformation at Inuyama Crustal Movement Observatory. For this purpose we used the record of the N-S strain component which is much affected by the precipitation. It's annual noise strain eq, amounting to 1.0×10-6 approximately, can be expressed in the formεq=aqi+blogqs, where a, b are the constants, qi the spring water (amounts of discharged water) from inner part of the observational gallery, and qs the spring water from the ground surface. The noise strain calculated by the above equation under the known values of a, b, qi, and qs has been subtracted from the original strainmeter record. As a consequence, the noise strain could be reduced to the value less than 20 per cent. The accurate measurements of qi and qs are necessary for the elimination of the noise strain associated with precipitation.抄録全体を表示PDF形式でダウンロード (725K) -
坪川 家恒, 長沢 工, 柳沢 道夫, 村田 一郎, 田島 広一, 佐藤 忠弘1971 年 16 巻 4 号 p. 209-231
発行日: 1971/08/25
公開日: 2011/07/05
ジャーナル フリーIt is well known that the tiltometer is one of the useful instrument for observation of the crustal movement. To detect the characteristic crustal movement accompanied by the earth's activity such as the earthquake, widely distributed observation station should be required. It is desirable that the instruments used at these stations satisfy the conditions such as high sensitivity, high stability, adoption of full automatic continuous recording system and easiness of setting and maintenance. Considering those requirements, the authors developed a small new type tiltometer after the principle proposed by one of the authors and named it TEM-Tiltometer (Tsubokawa's ElectroMagnetic Tiltometer). The characteristics of this instrument are the cross suspension pendulum which amplifies the tilting of the ground and the differential transformer as the transducer. It consists chiefly of above mentioned detector on a reset table, a recorder and electronic circuits. The reset table is used for the both purposes of calibration of the sensitivity and of preventing the record to escape from the proper range of recording chart. The authors set these tiltometers at Nokogiriyama Observatory in 1967 and at Akagane Station in 1968 and have carried out the observation of ground tilting. Their maximum sensitivity reached to 0.6"×10-3/1 mm on recording chart. This report contains the principle and the structure of the TEM-Tiltometer and some examples of observed results.抄録全体を表示PDF形式でダウンロード (10115K) -
―鳥取での経年変化について―住友 則彦1971 年 16 巻 4 号 p. 232-238
発行日: 1971/08/25
公開日: 2011/03/01
ジャーナル フリーIn order to detect anomalous geomagnetic changes related with earthquake occurrences, an observation of geomagnetic total intensity has been carried out at the Tottori Micro-Earthquake Observatory by means of a proton precession magnetometer since 1967. Geomagnetic total intensity is gradually decreasing with almost constant rate (22.5γ/year). By the detailed investigation for the rate of its secular variation, it may be suggested that annual change has slightly been recognized in the rate of monthly mean variation of geomagnetic total intensity. Daily mean values are conventionally used to calculate the difference of geomagnetic total intensity between Tottori and the Kakioka Magnetic Observatory, because they are free from an effect of anomalous local phase lag in the geomagnetic Sq variation of total intensity. On the other hand, D8t correction to daily mean values is made by using the Sugiura's D8t indices in order to remove the effect of magnetic storm disturbances. It can be concluded that the difference of daily mean values shows fairly stable constant value through a month, but is gradually decreasing through a year, and that the relative secular variation of Tottori to Kakioka is estimated to be about 1.5γ/year, of which value is seemed to be normal in Japan as compared with values obtained from the first and second order magnetic surveys made by the Geographical Survey Institute.抄録全体を表示PDF形式でダウンロード (817K) -
―潮位資料から求めた日本各地の土地の上下変動と地震予知―津村 建四朗1971 年 16 巻 4 号 p. 239-275
発行日: 1971/08/25
公開日: 2011/07/05
ジャーナル フリーまず第1報で求めた潮位の偏差の海域別平均値dhf(月平均),dHf(年平均)を1966年までのデタを加えて再計算し,海況と潮位の関係についての前報の結果を再確認した. 次に補正潮位hr(月平均)およびHr(年平均)を=h-Δha-ΔhfHf=H-ΔHfで計算した.ここに,h,Hは気圧の静力学的な影響を-10mm/mbとして取除いた月平均および年平均潮位,Δhaは前報で求めた平均年周変化である. hrあるいはHrはΔhfあるいはΔHrを計算する地点を適当に選べば,気象および海況の変化によると考えられる共通の不規則変化が取除かれ,短周期の土地の昇降が広い地域にわたつて一様に起つていないという仮定のもとに,それぞれの地点における土地の昇降をほぼ示すものと考えられる.1951～1965年の補正潮位の平均年変化量をこの期間の記録がほぼ完全であつて,人為的な沈下の影響がないと考えられる全国33箇所について平均すると-2.7±1.0mm/年(潮位低下あるいは土地の隆起)となつた.記録の不完全な地点も加えた計62箇所の平均年変化量の地域的な分布は,北海道および本州東岸で潮位上昇(沈下),その他は局地的な沈下を除き大部分潮位低下(隆起)となつている. 各地の補正潮位の変動を図に示した.この図をみると見掛けの周期が数年,全振幅数cm位のゆつくりしてなめらかな変動が現われている場所がある.今回の補正方法には時間的に平滑する手続きは含まれていないので,この変動はデータ処理の過程で見掛け上現われたものではなく地殼の昇降を表わしているとみられる.従来の水準改測結果を考え合せると地殻変動は一様に進行しているのではなく,長年変動傾向の上にこのようなゆつくりした昇降が重つているものと推定される. 最後に検潮資料によつて地震予知をおこなう可能性について考察した.地震に前駆すると考えられる地殼変動を(1)檀原の式で表わされるような震央近くの比較的限られた地域内の変動と(II)広い範囲にわたり一様な変動に区分し,時間的に(a)数十年,(b)数年～数箇月,(c)数日～数時間にわけて考えると,今回の補正方法では(II)型の変動は検出できないが,(I-a),(I-b)型の異常変動があれば検出できるはずである.このうち,(1-a)型の変動は,比較的容易に追跡できるがこれだけでは,地震発生の時期は推定できない.(1-b)型の変動は予知の手掛りとしてもつとも重要と考えられるが,今回の調査期間内では,地震時の変動が極めて明瞭に検出された1964年6月の新潟地震の場合でも地震前の変動を前記の一般の場所におけるゆるやかな昇降と比較して特に異常であるとは判別できなかつた.他の若干の例も同様である.さらに従来検潮による地震予知の可能性の1つの論拠となつていた1923年9月の関東大地震前の油壺の潮位変化を名古屋の変化と比較してみたところ,地震前数年間の(1-b)型の異常変動と考えられていた変化は名古屋の方にも大きく出ており,本研究の結果を参照すると,本州南沖の海況変動の影響による潮位変化であつて,異常な地殼変動の結果ではなかつたと解釈した方がむしろ合理的であることがわかつた.1944年の東南海地震前の変動についても同様である.したがつて,すくなくとも(I-b)型の変動を仮定する限り,既設の検潮所の分布密度,検潮儀の精度,これまでの解析方法で地震予知に有効な手掛りが得られた例はなく,今後得られる見込みも小さいという結論が得られた.ただし(II)型の変動を仮定すれば事情は全く異なるが,これを明らかにするには土地の絶対変動を求める方法の研究が必要である.抄録全体を表示PDF形式でダウンロード (3608K) -
山内 常生, 志知 龍一, 飯田 汲事1971 年 16 巻 4 号 p. 276-277
発行日: 1971/08/25
公開日: 2011/03/01
ジャーナル フリーPDF形式でダウンロード (160K) -
尾崎 幸男, 藤井 陽一郎1971 年 16 巻 4 号 p. 278-279
発行日: 1971/08/25
公開日: 2010/09/07
ジャーナル フリーPDF形式でダウンロード (1315K)
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