Journal of Physics of the Earth
Online ISSN : 1884-2305
Print ISSN : 0022-3743
ISSN-L : 0022-3743
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Volume 31, Issue 2
Displaying 1-4 of 4 articles from this issue
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  • PARTIAL DERIVATIVES OF RAYLEIGH WAVE PARTICLE MOTION
    Seiji TSUBOI, Masanori SAITO
    1983 Volume 31 Issue 2 Pages 103-113
    Published: 1983
    Released on J-STAGE: April 30, 2009
    DOIhttps://doi.org/10.4294/jpe1952.31.103
    JOURNAL FREE ACCESS
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    A theory was developed for the partial derivatives of ellipticity of Rayleigh wave particle motion at the free surface. It is based on the variational principle, and the partials are expressed in terms of eigenfunctions and an auxiliary integration of equation of motion. Model calculations for the Gutenberg crustmantle structure show a marked difference in depth dependence between the partials of ellipticity and those of phase velocity. The former decreases more rapidly with depth than the latter, implying a strong influence of near surface structure on the ellipticity. This characteristic is enhanced in higher modes. The new partials may be useful for studying near surface structures with horizontal components of higher mode Rayleigh waves.
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  • ESTIMATION OF THE PARAMETERS IN THE MODIFIED OMORI FORMULA FOR AFTERSHOCK FREQUENCIES BY THE MAXIMUM LIKELIHOOD PROCEDURE
    Yosihiko OGATA
    1983 Volume 31 Issue 2 Pages 115-124
    Published: 1983
    Released on J-STAGE: April 30, 2009
    DOIhttps://doi.org/10.4294/jpe1952.31.115
    JOURNAL FREE ACCESS
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    This paper proposes the maximum likelihood method to estimate the parameters of the modified Omori formula for aftershock sequences directly based on a time series of aftershocks. The likelihood function is derived by assuming that the aftershocks are distributed according to a certain non-stationary Poisson process. This method incidentally provides the asymptotic error distribution of the estimates. Statistical comparison of the characteristic parameters between two aftershock sequences, parameter estimation in case of the existence of the secondary aftershocks and other related problems are also discussed. As illustrative examples of calculations, some aftershock data are analyzed.
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  • ELASTICITY AND THERMAL EXPANSION OF A NATURAL GARNET UP TO 1, 000K
    Isao SUZUKI, Orson L. ANDERSON
    1983 Volume 31 Issue 2 Pages 125-138
    Published: 1983
    Released on J-STAGE: April 30, 2009
    DOIhttps://doi.org/10.4294/jpe1952.31.125
    JOURNAL FREE ACCESS
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    High temperature mechanical properties of a natural pyrope garnet have been investigated up to 1, 000K. The elastic moduli were measured by the Rectangular Parallelepiped Resonance (RPR) method. The frequencies of the lower 16 modes smoothly decrease with temperature from 300 to 1, 000K, and so do the elastic moduli.
    Thermal expansion of the specimen was measured by a dilatometric method. The least squares calculation based on an equation kY2-Y+E(θE, T)/Q=0(Y is relative volume expansion, and E(θE, T) is the Debye function) yields the constants Q=16.5MJ/mol, θE=698K, and k=1.50. From these constants, the Gruneisen's parameter γ0 (=Bo Vo/Q) and the pressure derivative of bulk modulus ∂B/∂P (=2k+1) at 0K are 1.2 and 4.0, respectively.
    By using these data, bulk moduli and other physical properties of this garnet are estimated up to higher temperatures (Table 2).
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  • ATTENUATION OF SHEAR WAVES IN DEEP SOIL DEPOSITS AS REVEALED BY DOWN-HOLE MEASUREMENTS IN THE 2, 300 METER-BOREHOLE OF THE SHIMOHSA OBSERVATORY, JAPAN
    Fumio YAMAMIZU, Noritoshi GOTO, Yutaka OHTA, Hiroshi TAKAHASHI
    1983 Volume 31 Issue 2 Pages 139-157
    Published: 1983
    Released on J-STAGE: April 30, 2009
    DOIhttps://doi.org/10.4294/jpe1952.31.139
    JOURNAL FREE ACCESS
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    Shear wave attenuation in deep soil deposits down to 2.3km in depth was directly and systematically measured at one of the deep-borehole observatories which were constructed for geophysical observations in the Tokyo metropolitan area. Introducing the newly designed SH-wave generator for an S-wave source, the down-hole measurements at 12 different depths were conducted down to 2.3km at intervals of 0.1-0.3km. Attenuation factors determined by the spectral ratio method were linearly inverted to QS-values under an assumption of frequency-independent QS.
    The obtained QS-values are 21±7, 51±6, and 48±11 from the top to the bottom of deep soil deposits, respectively, and larger than 150 in the substratum, for the frequency range of 3.5-20Hz. The QS for about 20 of the upper-most soil layer is faily consistent with known values which were estimated in shallower wells at various places. The substratum QS-value of 150 or over is not inconsistent with the crustal QS.
    The present measurement in such deep soil deposits is a new contribution to seismological and earthquake engineering studies. A significant effect of the attenuation factors upon the seismic waves is present by computing the amplification characteristics of deep soil deposits. At the present experimental site, the attenuation factor has a rather drastic effect upon the S wave in the period range shorter than 3sec.
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