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Volume 40 (1992)
- Issue 6 Pages 617-
- Issue 5 Pages 573-
- Issue 4 Pages 525-
- Issue 3 Pages 479-
- Issue 2 Pages 313-
- Issue 1 Pages 1-
Volume 40, Issue 5
Displaying 1-3 of 3 articles from this issue
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Sri Widiyantoro, Yoshimasa Kobayashi1992 Volume 40 Issue 5 Pages 573-584
Published: 1992
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSAn investigation of the shallow subsurface structure beneath a seismic line along the Yasu River, southeast coast of Lake Biwa, Central Japan, was carried out by the CDP (Common Depth Point) seismic profiling method. The survey location was intentionally chosen close to a deep drilling (900 m) site in order to correlate its results with the drilling log. The CDP profile reveals five "clear" horizons that can be correlated with the deep boring log.
The velocity analysis was done by the CVS (Constant Velocity Stack) method and in order to confirm the results it was also done by the Tau-p velocity analysis. The latter analysis gives the velocity function to every analyzed site enabling us to construct a depth section.
From the above results, it is recognized that there are gently dipping horizons toward Lake Biwa implying that the dipping motion has lasted through the period of sedimentation corresponding to the lower identified horizons. No fault was found below this investigation site.View full abstractDownload PDF (1619K) -
Fumiaki Kimata1992 Volume 40 Issue 5 Pages 585-599
Published: 1992
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSElectro-optical distance measurements (EDM) for the baseline networks of Sangane and Awagatake in the Tokai region began in 1978. The rangings of two baselines, Sangane-Zaoh and Awagatake-Magami, have been repeated four times a year on average. The directions of the baselines are parallel to that of the convergence of the Philippine Sea plate. In order to minimize the EDM error, distance measurements are carried out at sunset. The results of distance measurements for the 13 years are summarized as follows: (1) The accuracy of EDM around sunset is generally better than 5×10-7. (2) A NW-SE contraction and a NE-SW extension are common to both networks. A shear strain at a rate of 1 to 3×10-7/year is consistent with the geodetic surveys carried out in the last 100 years. (3) Both baselines, 80 km apart from each other, indicated a similar strain event, suggesting the accelerated contraction amounting to 1 to 2×10-6 in 1985-1987. The contraction is concordant with the change in geodetic tilt near Zaoh and the change in seismic activity in the Ise Bay area. The result obtained from observations might be evidence of the remarkable strain event that occurred in the Tokai region in 1985-1987.View full abstractDownload PDF (1590K) -
Isao Suzuki, Hitoshi Oda, Satoru Isoda, Toshiaki Saito, Kiyoshi Seya1992 Volume 40 Issue 5 Pages 601-616
Published: 1992
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSIt becomes possible to evaluate numerically eigenfrequencies of spheres with elastic anisotropy. Computation of eigenfrequencies on a single-crystal rutile sphere is made by using many isotropic free oscillation eigenfunctions of spheroidal and torsional modes. The eigenfrequencies are accurate enough to determine elastic constants of the rutile specimen by comparison with the observed resonance frequencies. The results are C11=267.59±0.73, C33=482.84±1.98, C13=148.09±0.88, C12=176.42±0.71, C44=123.43±0.19, and C66=192.85±0.43 GPa for the sample with density 4, 253.9±1.7 kg/m3 at room temperature.
Free oscillation of the rutile sphere is clarified by evaluating displacement distribution within the sphere, showing that most of the modes have much different patterns from those of isotropic materials.View full abstractDownload PDF (1384K)
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