巻号一覧
27 巻 (1981)
- 4 号 p. 225-
- 3 号 p. 155-
- 2 号 p. 75-
- 1 号 p. 1-
27 巻, 2 号
選択された号の論文の6件中1～6を表示しています
- |<
- <
- 1
- >
- >|
-
坂田 正治, 島田 誠一, 浜付 武重1981 年 27 巻 2 号 p. 75-84
発行日: 1981/09/30
公開日: 2010/09/07
ジャーナル フリーAn ocean bottom tiltmeter is under development for the purpose of detecting the precursors to predict earthquakes. The precursors having the periods between several minutes and a month are the object of the observation by the tiltmeter. The real-time signals of the tiltmeter will be transmitted by FM-FDM system through the submarine co-axial cable. This cable will also serve as the power line. The tiltmeter will be laid on the ocean bottom. Two force-balanced pendulum type and a bubble type tiltmeters are used as sensors. The result of the long term stability test of the sensors shows the long term drifts are less than 2×10-6 radian per month and that the reliabilities are within the order of 10-7 radian. The attitude of the sensors is controlled by a forced gimbal with the clamp mechanisms using the worm gears. A quartz thermometer is installed on the wall of the gimbal to monitor the temperature changes that affect the signals of sensors. The apparatus is composed of the pressure vessel which contains the gimbal and the transmitter and the platform which supports the pressure vessel. The ocean bottom tiltmeter is expected to be settled at about 20 m depth point near the marine observation tower about 1 km off Hiratsuka in Sagami Bay. The observation on the ocean bottom will give us fundamental informations about the quality of the coupling between the ocean crust and the tiltmeter on the sedimentary layer of sand and silt, and about the effects on the tiltmeter of the oceanographical factors such as the changes of the water temprature and the bottom current.抄録全体を表示PDF形式でダウンロード (2924K) -
遠藤 猛, 村田 一郎, 田島 広一, 柳沢 道夫, 里村 幹夫1981 年 27 巻 2 号 p. 85-92
発行日: 1981/09/30
公開日: 2010/09/07
ジャーナル フリーAbsolute measurements of gravity were carried out at Shizuoka University for the period from August 15 to August 20, 1980. As the observation site is located only 150 m apart from the Tomei Express Highway, ground vibration is predominant in a high frequency range (about 5 Hz). Because of the high-level ground vibration, the results obtained for each drop were scattered as much as ± 2.5 mGal. The mean gravity value obtained from thirty-three drops isg=979730.71±0.17 mGal. Some considerations show that the high-frequency ground vibration effects on gravity could cause scattering of ± 1 mGal even if ground vibration corrections were properly made. It becomes evident that such effects may be one of the most serious difficulties to be overcome for absolute gravimetries.抄録全体を表示PDF形式でダウンロード (779K) -
竹本 修三1981 年 27 巻 2 号 p. 93-101
発行日: 1981/09/30
公開日: 2010/09/07
ジャーナル フリーTwo typhoons (T7916 and T7920) passed through the southern part of Kinki district in 1979. On these occasions, remarkable changes of ground-strains were observed with two components of laser extensometers which were installed in the underground tunnel of the Amagase Observatory. Assuming that the atmospheric perturbation caused by the passage of typhoon is a negative load acting on an elastic homogeneous and isotropic half-space, we calculated the change of strain-field around a cavity and compared it with observational results . As a result, observed values were one order larger than calculated ones. This suggests that observed ground-strains of the order of 10-7 at the time of the passage of typhoon were caused by the another source, for instance, the change of the water level of Amagase reservoir which exists near the observatory.抄録全体を表示PDF形式でダウンロード (844K) -
瀬川 爾郎, 神沼 克伊, 春日 隆1981 年 27 巻 2 号 p. 102-130
発行日: 1981/09/30
公開日: 2011/07/05
ジャーナル フリーサーボ型加速度計を使用した船上重力計を製作した.この重力計はセンサーが線型であることと,頑強であること,また,鉛直ジヤイロとプラットフオームが分離されていることに特徴がある.この重力計は,昭和55年に製作され,砕氷船「フジ」の船上において,同年9月～10月の日本周辺航海でテストを行ない,ひきつづき,11月に出発した第22次南極観測のために使用された.この船上重力計は国立極地研究所と東京大学海洋研究所の略称により,NIPRORI-1型と命名された.本報告では,主にテスト航海でえられた結果について述べる.抄録全体を表示PDF形式でダウンロード (4100K) -
―設計の方針と試験観測―友田 好文, 藤本 博巳, 内山 昭憲, 大西 聡, 内藤 好裕1981 年 27 巻 2 号 p. 131-139
発行日: 1981/09/30
公開日: 2010/09/07
ジャーナル フリー海底の電気伝導度の異常を調べるために,新型の海底磁力計を試作し,試験観測を行なった. 設計の方針は次の通りである. 1)永久磁石の回転によって地球磁場を打消すこと 2)温度変化の影響は,独立に温度を測定し,計算機処理により,オフ・ライソで取除くこと 3)電池を長持ちさせるため,測定時だけ,間欠的に給電すること.である. この方針にもとついて一成分の試作機を製作し,柿岡で試験観測を行なった. 得られた結果は,気象庁地磁気観測所の標準磁力計の結果と細かい変化まで一致している.抄録全体を表示PDF形式でダウンロード (761K) -
―不動点の問題―中根 勝見, 藤井 陽一郎1981 年 27 巻 2 号 p. 140-147
発行日: 1981/09/30
公開日: 2010/09/07
ジャーナル フリーIn deducing crustal displacement vectors from geodetic data with two or more surveying epochs, selection of some fixed stations and accumulated survey errors determined by net-adjustment are the most important problems. In this paper, methods by which fixed stations should be selected are proposed as follows; (1) The fixed stations should be within the area where tectonic movements are as small as possible. The tectonic movements may be able to checked by tentativelly calculated shear strains. (2) If the fixed stations are selected far from the discussed area, survey errors will be much accumulated. On the other hand, location of the fixed stations should be out-side of the above-mentiond area. For instance, the 1923 KANTO earthquake was as large as M7.9 and supposed TOKAI earthquake will be as large as M8.0 respectively, then the areas influenced by these two earthquakes are as large as about 104 km2 res-pectively. The fixed stations shoud be outside of this areas. (3) Location of the fixed stations should be selected considering the tectonic move-ments. As drifting of the Philippine Sea plate is supposed in the direction NNW, the displacement vectors may be neglected when the fixed stations line is selected parallel to the direction of the plate motion, but when the fixed stations line is selected perpendi-cular to the drifting of the Philippine Sea plate the movement may be ref rected in the calculated displacement vectors. In discussing crustal movement of KANTO-TOKAI district, we select the fixed statians TSUKUBASAN, TERUISHIZAN, DODAIRAYAMA, KOKUSHIDAKE II, KAIKO-MAGADAKE and ENASAN on the basis of above mentioned criteria. The fixed stations line is selected perpendicular to the direction of the Philippine Sea plate motion and located about 150 km far from the convergent plate boundary of the Philippine Sea plate.抄録全体を表示PDF形式でダウンロード (859K)
- |<
- <
- 1
- >
- >|