巻号一覧
19 巻 (1973)
- 4 号 p. 179-
- 3 号 p. 125-
- 2 号 p. 67-
- 1 号 p. 1-
19 巻, 2 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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萩原 幸男1973 年 19 巻 2 号 p. 67-69
発行日: 1973/07/25
公開日: 2010/09/07
ジャーナル フリーG1 was practically computed from gravimetric and terrain data of Tanzawa Mountains as presented in the previous paper [1]. The present paper is devoted to obtain the plane distribution of Gl over the area concerned. We can see in the map of G1 that negative zones distribute over mountain peaks and ridges, while positive zones over valleys.抄録全体を表示PDF形式でダウンロード (2227K) -
田島 広一, 萩原 幸男1973 年 19 巻 2 号 p. 70-75
発行日: 1973/07/25
公開日: 2010/09/07
ジャーナル フリーMany authors [1-6] have recently reported secular gravity changes detected by means of repetitions of gravimetric surveys in Japan. In order to check the reliability of gravity change, the authors carry out gravity measurements at bench marks over ground subsidence areas, i.e., Chigasaki, Kanagawa Pref. and Mobara, Chiba Pref., where secular changes in bench mark elevations are known. Two LaCoste gravimeters, G34 and G210, are used. As compared with values previously observed at the same bench marks, the gravity changes associated with elevation changes are evidently found in Mobara Area. On the contrary, a relation between gravity and elevation changes are not clear in Chigasaki Area.抄録全体を表示PDF形式でダウンロード (541K) -
古沢 保, 尾上 謙介, 高田 理夫1973 年 19 巻 2 号 p. 76-84
発行日: 1973/07/25
公開日: 2010/09/07
ジャーナル フリーThe Donzurubo Crustal Movement Observatory was established for the purpose of studying the crustal deformation and the prediction of earthquakes in 1967, and the continuous observation of ground-strain and -tilt has been carried out by the superinvar bar and superinvar wire extensometers, horizontal pendulum tiltmeters and the watertube tiltmeters. Furthermore, for the purpose of obtaining the telemetric digital record of crustal deformations, a new recording system was devised and applied to the silica-tube extensometers. This system was made up of crystal clock, scanner, photoelectric transmitter, digital counter and digital printer. Comparing with the usual photographic records, the records with the same accuracy were obtained. As an example of observed results, analysis of two tidal components (M2 and 01) were made from records during 45 days.抄録全体を表示PDF形式でダウンロード (3169K) -
田中 寅夫1973 年 19 巻 2 号 p. 85-92
発行日: 1973/07/25
公開日: 2011/03/01
ジャーナル フリーOceanic influences upon the earth tidal tilts and strains observed at Barim in China, and Kamigamo, Osakayama, Kishu, Akibasan and Oura in Kinki District, Japan, have been estimated for the wave O1 in the same way as in previous reports. Theoretical earth tides including the oceanic influences have been compared with the observed values. The result are summarized in Tables IV and V, together with those of the wave M2. In the tables amplitude ratios and phase differences between the observed earth tides and those calculated for the Gutenberg earth model are shown for each component of tilts and strains at the above stations. The E-W component of tilt at Barim, E-W, N-S and N61°E-S61°W components of strains at Osakayama, and N30°W-S30°E and N60°E-S60°W components of strains at Kishu are well explained by the Gutenberg earth model, and two components of tilts at Akibasan are better explained by a modified Gutenberg model with a realistic crustal structure. The discrepancies between the observed and calculated values on the other components may be attributed to several factors such as errors of calibration, shortness of analyzed records, deficiency of the sensitivity of instruments, meteorological disturbances, coupling of instruments to the ground, effects of stress concentration around observation vaults, crustal heterogeneity, and errors of estimation of the indirect effects.抄録全体を表示PDF形式でダウンロード (1013K) -
笠原 慶一1973 年 19 巻 2 号 p. 93-99
発行日: 1973/07/25
公開日: 2011/03/01
ジャーナル フリーLevelling data in several tectonic areas are compared with tiltmeter readings at adjacent stations. This is to examine the function of a crustal movement monitoring system which is based on the complemental use of continuous observations with geodetic surveys. Briefly speaking, this idea seems successful so far as the present examples are concerned. Rhythms of secular tilt accumlation which are read on tiltmeters are almost consistent with the levelling data. With respect to the rate and the azimuth of predomi-nant tilting, however, the two sorts of data are not consistent, reflecting the inhomo-geneous crustal structures. Examining the data more precisely, we sometimes notice significant phase lag of the tiltmeter curves to the levelling curves (vertical land movement). This effect may be attributed to migration of the crustal movements. A brief discussion has been developed, from this point of view, to clarity migration of the land upheaval in the Niigataand Miura peninsula areas.抄録全体を表示PDF形式でダウンロード (720K) -
中川 一郎, 里村 幹夫, 瀬戸 孝夫, 長谷川 康正, 塚原 弘一, 萩原 幸男, 田島 広一, 井筒屋 貞勝, 村田 一郎, 中井 新二 ...1973 年 19 巻 2 号 p. 100-112
発行日: 1973/07/25
公開日: 2010/09/07
ジャーナル フリーIn gravity measurements, it is naturally presumed that the gravity values obtained are disturbed by certain effects. A thorough investigation for those effects is an essential problem on gravity measurements. Experiments for investigating the characteristics of LaCoste & Romberg gravimeters (model G) were cooperatively carried out at Kakioka in January 1973. The following points were thoroughly examined for 9 gravimeters (G-29, 31, 34, 118, 123, 124, 196, 210 and 305) in the experiments. (1) Calibration on scale factor of the gravimeters, along the 3 routes between Tokyo and Kakioka (gravity difference + 202.7 mgal), between Kakioka and Hitachi (gravity difference + 51.3 mgal), and between Kakioka and Mt. Tsukuba (gravity difference-169.4 mgal). (2) Check on cross levels of the gravimeters. (3) Effect by turning the measuring screw of the gravimeters. (4) Effect due to voltage change of the connecting battery. (5) Effect due to meteorological disturbances. (6) Influence due to vibration during the transportation. The following conclusions were obtained through the present experiments. (1) Discrepancy among the scale factors of the 9 LaCoste & Romberg gravimeters was found to be about 2-3×10-4. An attention must, therefore, be paid on an accuracy of scale factor of the gravimeter, in case when a gravity measure-ment is carried out for large gravity difference. (2) Sudden voltage change of the connecting battery gave serious effect to the gravimeter, even for one hour. The voltage must be held as constant as possible during the measurement. (3) No effect was clearly detectable by temperature and pressure changes. (4) Influence amounting to about or less than 0.01 mgal was found by vibration during the transportation. There found some differences among the type of gravimeters, but the present results were rather better, in general, than those of the previous experiments. The present results show that an accuracy of ± 0.01 mgal is attained through careful measurement by using the LaCoste & Romberg gravimeters.抄録全体を表示PDF形式でダウンロード (1490K) -
力武 常次1973 年 19 巻 2 号 p. 113-115
発行日: 1973/07/25
公開日: 2011/03/01
ジャーナル フリーStatistics of ultimate strain of the earth's crust is made on the basis of levelling and triangula-tion data over earthquake areas. The mean value of ultimate strain so is obtained as 5.3 × 10-5 with a standard deviation Q amounting to 3.3× 10-5 on the assumption that the deviation from the mean value is governed by a Gaussian distribution. Assuming that crustal strain increases linearly with time t from an appro×imately zero value immediately after an earthquake, which occurred at t=0, the probability of having a crustal break or an earthquake occurrence during a time in-terval from 0 to t can be calculated from Eo and σ along with the data for strain accumulation over the area concerned as brought out with repetitions of geodetic survey. Applying the above theory to an area south-west of Tokyo, where an earthquake of magni-tude 7.9 took place in 1923, the probabilities for repetition of a similar earthquake there are esti-mated as 0.2, 0.5 and 0.8 for periods 1925-1980, -2030, and -2080.抄録全体を表示PDF形式でダウンロード (323K) -
坪川 家恒1973 年 19 巻 2 号 p. 116-119
発行日: 1973/07/25
公開日: 2010/09/07
ジャーナル フリーScholz et al, explained precursory phenomena and their durations before earthquakes by dilatancy of the crust, and proposed the relation between the duration period and the magnitude of the earthquake expected which is quite near to the relation proposed by the writer in 1969. The writer also points out the duration period due to dilatancy must be shortened for an earthquake larger than M7, 0 and disappears larger than about M7, 7.抄録全体を表示PDF形式でダウンロード (388K) -
中井 新二1973 年 19 巻 2 号 p. 120-121
発行日: 1973/07/25
公開日: 2010/09/07
ジャーナル フリーAn accuracy of ±6 Fugal has been obtained by repeating the precise gravity measurements between Mizusawa and Tokyo with a single gravimeter, L&R G305. So far as we use same gravimeter to detect any gravity change, we may only pay attention to the change of scale constant and need not necessarily the exact calibration.抄録全体を表示PDF形式でダウンロード (275K)
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