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Volume 17, Issue 3
Displaying 1-6 of 6 articles from this issue
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Sadao MIYAMOTO1964 Volume 17 Issue 3 Pages 131-138
Published: September 25, 1964
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSThe first report explains the relation between abnormal phenomena of the special astatic magnetometer and earthquakes.
Table 1 in this paper indicates the earthquakes of Fig. 7 and 8 of the first paper.
Table 2 in this paper explains abnormal phenomena by this magnetometer from Sep. 1 in 1959 to Jan. 31 in 1961.
Therefore, please compare Table 1 and 2 with Fig. 7 and 8 in the first report.View full abstractDownload PDF (504K) -
Katsutada KAMINUMA, Tomowo HIRASAWA1964 Volume 17 Issue 3 Pages 139-147
Published: September 25, 1964
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSThe records of Mantle Love waves of the Iranian earthquake of September 1, 1962 (19h 20m 38.5s G. M. T., 35.6 N 50.0 E M: 7 3/4) are analyzed for the purpose of obtaining the phase velocity and specific dissipation factor.
The local phase velocity in a part of central Japan for the periods 70 to 110sec is derived from seismograms (G1, G2) of Tsukuba, Hongo and Matsushiro. The results confirm the former ones obtained by Aki and Kaminuma (1963) from the Aleutian shock of March 9, 1957.
From records of G1 and G3 at Tsukuba, a phase velocity curve for the great circle path through Tsukuba is obtained. Making use of the phase velocity the specific dissipation factors (Q) for mantle Love wave are calculated for the periods 50 to 150sec. There is a minimum value of Q about at the period 90sec.View full abstractDownload PDF (614K) -
Yasuo SHIMAZU, Yoshiteru KONO1964 Volume 17 Issue 3 Pages 148-157
Published: September 25, 1964
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSUnsteady mantle convection is studied as a continuation of the previous paper (Part 1). Thermal interactions between the crust and the upper mantle are our main interests.
Numerical calculations are performed until a reversal of the initial temperature distribution is realized. Variations in isotherm, speed, stress and heat flow through the Moho are obtained. The speed increases exponentially and reaches the order of 1cm/year. The stage of the maximum stress comes 3-4×107 years earlier than the stage of the maximum heat flow. The former stage may correspond to epiorogenic submarine volcanism (formation of fractures) while the latter to plutonic activity (formation of granitic batholiths).
Considering the time scale of actual tectogenesis (-108 years) and the reasonable range of convection speed (<102cm/year), the mean viscosity of the upper mantle is estimated as 1021-1022 poises. After the convection is grown sufficiently (>10-3cm/year) the thermal state of the crust has no effect on its subsequent development.View full abstractDownload PDF (813K) -
Mamoru KATSUMATA1964 Volume 17 Issue 3 Pages 158-165
Published: September 25, 1964
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSIn this paper, a method to determine the magnitude of deep-focus earthquakes in and near Japan from the observation data of Japan Meteorological Agency is proposed.
The relation between the maximum amplitude of earthquake motion (mainly S waves) at a certain epicentral distance and the depth of the earthquake origins is approximately expressed by log10A=C-ΣCn(H/R)n where A is the amplitude, R is the radius of the earth, H is the depth of the origin, C=M-C0 (M means the magnitude), and each Cn is a certain constant.
From the above equation, the magnitude is determined by M=log10A+K where K=C0+ΣCn(H/R)n.
For the sake of convenience, the Ks for several distances and depths are given in a table.View full abstractDownload PDF (570K) -
Kumizi IIDA, Mineo KUMAZAWA, Kazunari SUZUKI1964 Volume 17 Issue 3 Pages 166-167
Published: September 25, 1964
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSDownload PDF (214K) -
Yasuo SATÔ, Tatsuo USAMI1964 Volume 17 Issue 3 Pages 167-169
Published: September 25, 1964
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSDownload PDF (204K)
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