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Volume 15, Issue 2
Displaying 1-12 of 12 articles from this issue
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Kyozi TAZIME1962 Volume 15 Issue 2 Pages 59-66
Published: June 30, 1962
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSIt has been found that all matrices expressing displacement potentials are already given by that determining reflection and refraction coefficients. Therefore, displacement potentials can be easily developped by reflection and refraction coefficients. Some results obtained here are compared with that obtained by the other method in the previous paper (TAZIME, 1958). The both methods have arrived at the same expression of displacement potential.View full abstractDownload PDF (478K) -
Hikaru WATANABE1962 Volume 15 Issue 2 Pages 67-78
Published: June 30, 1962
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSAt Abuyama Seismological Observatory the routine seismological observation is being made with sensitive seismographs of short period. The results of the observation show that about two hundred microearthquakes of M about 1 up to 3 occurred in the area within 20km. from the observatory during 1959.
According to the space distribution of foci of the microearthquakes and the time series of their occurrence, most of the microearthquakes are classified into earthquake sequences which are characterized by the time distributions of the accumulated strain release shown in Figs. 5-8. It may be seen from Figs. 7 and 8 that two different types of the graphs are well expressed by the equations (5.7) and (5.8) which are obtained from the creep characteristics of rocks under high pressure.
On the basis of this fact it is suggested that the characteristics of the sequences of microearthquakes may be adequately explained by the models as illustrated in Figs. 9 and 11.View full abstractDownload PDF (2838K) -
Hikaru WATANABE1962 Volume 15 Issue 2 Pages 79-85
Published: June 30, 1962
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSThe elastic strain release characteristics for the sequences of severe earthquakes were investigated by the method as was described in the preceding paper (part 1 of the same title).
It is interesting to note that the curves of the accumulated strain release for the sequences of severe earthquakes (shown in Figs. 4 & 5) are represented by the same formulas as the curves for the micro-earthquake sequences are represented, in spite of a large difference of released energy.View full abstractDownload PDF (691K) -
Kazuo HAMADA, Kyozi TAZIME1962 Volume 15 Issue 2 Pages 86-94
Published: June 30, 1962
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSRelations between wave-lengths and displacements have been obtained as shown in Figs. 14 and 16, which may be appraximated by Fig. 17. Any phase near eq. (9.4) alone have large amplitude in comparison with the other phases. Therefore, the maximum amplitude will be given by TVp1/H≈4.
The vertical distributions of amplitude have been calculated as shown in Figs. 19 to 21 which give also informations as to particle orbits.View full abstractDownload PDF (686K) -
Ikuei MURAMATU1962 Volume 15 Issue 2 Pages 95-107
Published: June 30, 1962
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSThe meaning of the maximum velocity response spectrum SV obtained by an electric resonance analyser cannot be explained by expressing the ground motion by Fourier series and it is also difficult to explain SV(h) by the expression by Fourier integral.
When the spectrum of ground motion is expressed by “a group of sinusoidal vibrations with finite duration”, SV for an arbitrary damping constant h is denoted by the following equation:
SV≠a/p1/2h{1-exp(-h/√1-h2πκ)},
where a, p/2π and πκ/p are the amplitude, the frequency and the duration of a component of the acceleration spectrum of the ground motion, respectively. Examples of SV are well explained by the equation.
It is also pointed out that the fact that SV(h≥0.2) is almost constant for any natural frequency of the analyser does not necessarily indicate that the velocity spectrum of ground motion is regarded as constant. And it may be concluded that SV expresses the property of a short period vibration which is generally contained predominatingly in an acceleration seismogram.View full abstractDownload PDF (742K) -
Estimation of Earthquake Danger, Part 1Ikuei MURAMATU1962 Volume 15 Issue 2 Pages 108-115
Published: June 30, 1962
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSIn this paper, an expression for the estimation of the earthquake danger with due consideration of the vibrational characteristics of earthquake motion was stated, where the maximum value of the effects of the earthquake motion to be expected and its vibratioanl characteristics were seperated by inducing the conception of a standard ground and a standard structure.
From the expression stated here, the expectation of maximum acceleration of earthquakes given by H. Kawasumi was examined and further the expression for the estimation of earthquake danger which was proposed by S. V. Medvedev and that which will be obtained by using G. W. Housner's SV were derived.View full abstractDownload PDF (671K) -
Ken-ichi GOTO1962 Volume 15 Issue 2 Pages 116-121
Published: June 30, 1962
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSUnder the assumption that the distribution of after-shocks indicates the form of focal region of earthquake, 30 earthquakes are classified into 3 kinds (Table 1) according to the modes of occurence.
About the earthquakes of single occurrence type, i. e. the simplest form of focal region, the relation between area (A), thickness (T), dimension ratio (D/T), energy per unit volume (E/V), strain (S) and magnitude are investigated. (Figs. 1-6)
It is interesting that the larger an earthquake is, the smaller E/V or S is.View full abstractDownload PDF (430K) -
Hitoshi TAKEUCHI, Masanori SAITO, Naota KOBAYASHI, Ichiro NAKAGAWA1962 Volume 15 Issue 2 Pages 122-137
Published: June 30, 1962
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSFollowing the way in a previous paper, Fourier analysis of gravimeter records of the Chilean earthquake of May 22 in 1960 obtained in Kyoto is extended to larger wave numbers. The period range covered by the present study is from 66.4min. to 8.4min. Spectral peaks corresponding to the earth's spheroidal oscillations of n=2 to 12 are seen in the results shown in Fig. 1. Observed oscillation periods seem to be a little longer than those predicted by Pekeris and others for the Gutenberg model. This may be due to a low velocity zone being nearer to the earth surface under Japan.View full abstractDownload PDF (1251K) -
Ryosuke SATO1962 Volume 15 Issue 2 Pages 138-140
Published: June 30, 1962
Released on J-STAGE: March 11, 2010
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Yoshio YAMAZAKI1962 Volume 15 Issue 2 Pages 140-142
Published: June 30, 1962
Released on J-STAGE: March 11, 2010
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Takeo MATUZAWA1962 Volume 15 Issue 2 Pages 142-143
Published: June 30, 1962
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSDownload PDF (261K) -
Sigeru KANDA1962 Volume 15 Issue 2 Pages 143-145
Published: June 30, 1962
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSDownload PDF (404K)
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