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Volume 26 (1980)
- Issue 4 Pages 227-
- Issue 3 Pages 137-
- Issue 2 Pages 75-
- Issue 1 Pages 1-
Volume 26, Issue 2
Displaying 1-10 of 10 articles from this issue
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Hiromi FUJIMOTO, Yoshibumi TOMODA1980 Volume 26 Issue 2 Pages 75-81
Published: August 30, 1980
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThree important problems exist in constructing a superconducting gravimeter. These are (1) to keep liquid helium as long as possible, (2) to make the sensor mass astatic, and (3) to use a high sensitivity detector to measure small variation of position of the sensor mass. A superconducting gravimeter with a diameter of 15 mm is designed and set up in liquid helium storage tank of 50 liters. This device will be used for gravity measure ment continuously for more than a month. The smallest vertical force gradient of the device which we have used corresponds to a resonant frequency of 2 Hz of the sensor mass. Variation of position of the sensor mass will be detected with the sensitivity of 1 Angström (10-8 cm) by use of a superconducting quantum interference device(SQUID). By use of this device it is expected that gravity variations can be measured with a sensi tivity better than 10-9 G.View full abstractDownload PDF (784K) -
Yoichi FUKUDA, Ichiro NAKAGAWA1980 Volume 26 Issue 2 Pages 82-90
Published: August 30, 1980
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSVarious kinds of geodetic data; for examples, levelling, triangular, gravimetric and other data, have recently been stored in relation to researches for earthquake prediction and other purposes. Under these circumstances, to develop a data processing system for efficient utilizations of such geodetic data would be considered one of the most important and urgent problems. On the other hand, a graphic display unit of refreshing-type has recently been showed its capability to the full for handlings of graphically represented data in computer science. Therefore, its application to geodetic data which would be considered suitable for the graphic representation brings many advantages to data processing. A computer program for time-space representation of the geodetic data has been developed by means of a graphic display unit of refreshing-type. The main procedure of the program consists of two steps. One is an interpolation for missing values of the geodetic data in time-space domains, and the other is a graphic display of the interpolated data. The program was applied to gravimetric data obtained around Lake Biwa in order to demonstrate its efficiency. In addition, some problems of this technique are briefly discussed for the future studies.View full abstractDownload PDF (2554K) -
Michio YANAGISAWA1980 Volume 26 Issue 2 Pages 91-103
Published: August 30, 1980
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSEarth tides observations have been carried out by multiple set of TEM tiltmeters and a set of V-M horizontal pendulum tiltmeter at the Nokogiriyama Crustal Movement Observatory during the period from November 1967 to August 1975 and from December 1977 to February 1979. The dataprocessing is made by the harmonic analysis method provided by Inter national Center of Earth Tides, and the results are compiled in the tables presented in this paper.View full abstractDownload PDF (2459K) -
Yoichiro FUJII, Katsumi NAKANE1980 Volume 26 Issue 2 Pages 104-112
Published: August 30, 1980
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThe 1st order triangulation near the Suruga Bay, Honshu, Japan was carried out three times in 1883/1891, 1931, 1973 respectively. The earth's horizontal strains were deduced from these survey data. In the first report [1], net adjustment of the triangulation in 1931 was carried out under the assumption that the positions of the two stations, KENASHIYAMA and DAIMUGENYAMA, are not changed during 1883/1891-1931 . In the second report, geodetic positions of the three stations, TANZAWAYAMA, KENASHIYAMA, and DAIMUGENYAMA in 1931 are deduced from the survey data that are obtained under the assumption of some fixed stations located far from the discussed region. These estimated positions of the three stations are adopted in the net adjustment. Net adjustments of the triangulations in 1883/1891 and 1973 are the same as in the first report. Directions of two principal strain axes and maximum shear strain in each geodetic triangle in the second report are the same as in the first report, while dilatation and side-length changes are different each other. Horizontal displacement vectors of the triangulation stations during 1883/1891-1931 are obtained referring to the fixed stations far from the convergent boundary of the Philippine Sea plate. From these data, it is concluded that the Izu peninsula is drifting to NNW by 2.3 cm/yr and the Tokai district is compressed to NNW by 1.1 cm/yr.View full abstractDownload PDF (885K) -
Shuzo TAKEMOTO1980 Volume 26 Issue 2 Pages 113-123
Published: August 30, 1980
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSFour extensometers with laser interferometer systems were installed in the disused race tunnel at the Amagase Crustal Movement Observatory. Two of them (EL-1 and EL-V) are super-invar bar extensometers with laser interferometer systems consisting of simple laser sources, Michelson interferometers and photodetecting equipments with image-sensors. The remaining two components (L-1 and L-2) are laser extensometers with a frequency-stabilized laser source. EL-1 and L-1 are orientated along the axis of the tunnel and L-2 is orientated across the tunnel. EL-V is a vertical component. Using continuous data obtained from these extensometers for the period of 390-day, the distortion of tidal strain field due to the cavity effect has been investigated. There is a good agreement between the observed data and the cavity effect calculated with finite element techniques for the actual tunnel profile.View full abstractDownload PDF (1052K) -
Harold SOLOMON1980 Volume 26 Issue 2 Pages 124-125
Published: August 30, 1980
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSDownload PDF (282K) -
Yoshio UEDA1980 Volume 26 Issue 2 Pages 126-127
Published: August 30, 1980
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSDownload PDF (223K) -
Fumiaki KIMATA, Tsuneo YAMAUCHI, Torao TANAKA, Yoshinobu HOSO1980 Volume 26 Issue 2 Pages 128-129
Published: August 30, 1980
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSSide-by-side distance measurements by two Geodimeters were made in order to investigate the origin of fluctuations in measured lengths with a period from a few tens of minutes to one hour. The light paths and distances for the instruments were set to be close to each other, and the measurement was carried out within a few hours before and after sunset for four consecutive days. A weak correlation was found in slow fluctuations with a period of one to four hours in the two lengths observed with the two Geodimeters; the is considered to be due to the change of light velocity along the path. On the other hand, there can hardly be seen any certain relationship in the fluctuations with short periods (10-20 minutes), so that they are presumably caused by the instrumental error. It is also suggested that an accuracy higher than ±1.0X10-6 will be obtainable in the distance measure ments with Geodimeter 6BL by repeating measurements many times within a few hours around sunset.View full abstractDownload PDF (259K) -
Fumiaki KIMATA, Iwao FUJII, Masarp NAKAMURA1980 Volume 26 Issue 2 Pages 130-131
Published: August 30, 1980
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSA small aperture (20-65 m) bench mark array for spirit-level survey has been installed on Yake-Dake Volcano in October 1977. The levelling net which is located 0.5 km from the main active fumarole, consists of three loops, with a total length of 529 m. Spirit level surveys have been annually conducted in Oct. 1977, Sept. 1978 and Oct. 1979. Loop closures afford a precision of about 0.5√mm (D; loop length, km). Tilt vector from 1977 to 1979 shows a dip of about 10μradians/year towards NNW which means a relative upheaval of the sumit of Yake- Dake.View full abstractDownload PDF (1425K) -
Yukio HAGIWARA1980 Volume 26 Issue 2 Pages 132-133
Published: August 30, 1980
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSMost of active faults are located in negative short-wavelength Bouguer anomaly zones in Northeast Japan. Exceptionally in the shallowfocus seismic belt around the tip of Philippine Sea Plate boundary, active faults coincide with a positive short-wavelength Bouguer anomaly zone.View full abstractDownload PDF (283K)
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