Journal of Physics of the Earth
Online ISSN : 1884-2305
Print ISSN : 0022-3743
ISSN-L : 0022-3743
Volume 14, Issue 1
Displaying 1-3 of 3 articles from this issue
  • Tuneto KURITA
    1966 Volume 14 Issue 1 Pages 1-14
    Published: 1966
    Released on J-STAGE: April 30, 2009
    JOURNAL FREE ACCESS
    Several attempts have been made to determine a Q distribution in the mantle using the amplitude ratio of multiply reflected core phases or the diminution of body wave amplitudes with an increase in epicentral distance. When seismic waves travel in an anelastic medium like the earth, it is expected that not only the amplitudes of the waves diminish but also their periods will lengthen. In the present study, the spectral analysis of long-period P-waves from an intermediate earthquake has revealed the phenomenon that the spectral peak with a period of about 10 seconds moves toward longer period side with the increase in epicentral distance. Records of vertical component obtained at 23 stations with epicentral distances from about 37 to 105 degrees were used in the analysis. By comparing this phenomenon with the transition of the maximum spectral peak expected from a theoretical model, a Q distribution in the mantle has been tentatively estimated.
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  • Naoyuki FUJII, Seiya UYEDA
    1966 Volume 14 Issue 1 Pages 15-26
    Published: 1966
    Released on J-STAGE: April 30, 2009
    JOURNAL FREE ACCESS
    Thermal history calculations have been made on a once-molten earth model: the earth is assumed to have undergone extensive melting in its early stage and the formation of the core and mantle with a proto-crust completed 4.5×109 years ago. Necessary magnitude of thermal conductivity, including the radiative components, for such an earth to cool to the present state has been obtained in terms of the opacity value as 1-3cm-1. If the earth's mantle became to consist of large crystals after the recrystallization, such a small value of opacity may be compatible with the results of thermal and optical measurements.
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  • E.A. LUBIMOVA
    1966 Volume 14 Issue 1 Pages 27-36
    Published: 1966
    Released on J-STAGE: April 30, 2009
    JOURNAL FREE ACCESS
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