Zisin (Journal of the Seismological Society of Japan. 2nd ser.)
Online ISSN : 1883-9029
Print ISSN : 0037-1114
ISSN-L : 0037-1114
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Volume 15, Issue 3
Displaying 1-6 of 6 articles from this issue
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  • On the Combined Observations of the Crustal Deformations at Some Observatories inside a Small Area (at Osakayama)
    Izuo OZAWA
    1962 Volume 15 Issue 3 Pages 157-168
    Published: September 25, 1962
    Released on J-STAGE: March 11, 2010
    DOIhttps://doi.org/10.4294/zisin1948.15.3_157
    JOURNAL FREE ACCESS
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    It is one of the most essential conditions of the crustal deformations that the areas of the deformations are large.
    In order to determine whether the changes recorded with extensometrs or tiltmeters show the real deformations over the large areas of the crust or not, some observatories are set near the ones which have been in use at Osakayama Observatory.
    From these combined observations, making comparison the amplitude ratios of the annual variations of the same components in every observatory, the wave-lengths of them are calculated. And in order to expose the micro-anomalies before and after the Himejiearthquake and the Kitamino-earthquake, the tidal variations are entracted from the observed curves.
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  • On the Forms of S and ScS Waves of Some Deep Earthquakes
    Michio OTSUKA
    1962 Volume 15 Issue 3 Pages 169-182
    Published: September 25, 1962
    Released on J-STAGE: March 11, 2010
    DOIhttps://doi.org/10.4294/zisin1948.15.3_169
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    The seismograms of deep earthquakes are simple in general. Among them are often found the similar solitary waveforms of S or ScS. On the assumption that these waveforms represent the delta responses of the seismic wave paths, we can get a kind of information regarding the nature of the earth's mantle.
    In this paper, we first deal with ScS phases of the two deep earthquakes. Assuming Knopoff's model, Q values of the earth's mantle are calculated to be about 350 for the lower part and 150 for the upper part. These values are in fair agreement with other authors' results. It is also shown that the waveforms of S phases are represented by the repetition of waveform of ScS.
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  • On the JEFFREYS' model of the earth crust and mantle
    H. TAKEUCHI, M. SAITO, N. KOBAYASHI
    1962 Volume 15 Issue 3 Pages 183-194
    Published: September 25, 1962
    Released on J-STAGE: March 11, 2010
    DOIhttps://doi.org/10.4294/zisin1948.15.3_183
    JOURNAL FREE ACCESS
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    Studies are made on the JEFFREYS' model of the earth's crust and mantle, in which density ρ and rigidity μ in the mantle are 5/4 and 20/9 times those in the crust, respectively. Dispersion curves obtained are shown for the fundamental (Fig. 1 and 7) and first overtone (Fig. 2 and 8) RAYLEIGH and LOVE waves. Corresponding displacement distributions in the crust are shown in Fig. 3-4 (fundamental RAYLEIGH), 5-6 (first overtone RAYLEIGH), 9 (fundamental LOVE) and 10 (first overtone LOVE), respectively. Lastly excitations of these modes by a wave origin of DIRAC type in space and time are discussed.
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  • Crustal structure in Japan from the phase velocity of Rayleigh waves
    Katsutada KAMINUMA, Keiiti AKI
    1962 Volume 15 Issue 3 Pages 195-218
    Published: September 25, 1962
    Released on J-STAGE: March 11, 2010
    DOIhttps://doi.org/10.4294/zisin1948.15.3_195
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    The crustal structure in Japan was studied by Aki (1961) from the phase velocity of Rayleigh waves from a Samoa Shock recorded by the net work of many seismologic stations operated by the Japan Meteorological Agency.
    In the presnt study, we used the records of the Aleutian Shock of Mar. 9, 1957 (14h 22m 27s G. M. T., 51N 175W, M: 8-8 1/2). The direction of approach was at right trend of Japanses Islands for the waves studied in the previous paper, but is parallel to it in this report. The regions, South Hokkaido, Hokuriku, Kii, etc, which were not covered by Aki's paper, are included in this paper.
    The principal results are as follows.
    1. The values of phase velocity in the western Japan agree in both cases. But in the central Japan there is a little difference in the value between both cases.
    It may be considered that the phase velocity depends on the direction of approach in this region.
    2. A map of crustal thickness in Japan is tentatively drawn from the result obtained by the phase velocity method.
    3. The east side and the west side of the Fossa Magna are separated in the diagram showing the relation between the phase velocity of Rayleigh waves with the period of 30sec and the average Bouger anomaly.
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  • Model Experiments Applied to Seismology
    Keichi KASAHARA
    1962 Volume 15 Issue 3 Pages 219-237
    Published: September 25, 1962
    Released on J-STAGE: March 11, 2010
    DOIhttps://doi.org/10.4294/zisin1948.15.3_219
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  • Seismic Model Study
    Akio TAKAGI
    1962 Volume 15 Issue 3 Pages 238-254
    Published: September 25, 1962
    Released on J-STAGE: March 11, 2010
    DOIhttps://doi.org/10.4294/zisin1948.15.3_238
    JOURNAL FREE ACCESS
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