Zisin (Journal of the Seismological Society of Japan. 2nd ser.)

Complex Roots in the Characteristic Equation

Kyozi TAZIME

1965 Volume 18 Issue 3 Pages 133-141
Published: September 25, 1965
Released on J-STAGE: March 11, 2010

DOIhttps://doi.org/10.4294/zisin1948.18.3_133

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Complex roots contained in the characteristic equation have been found analytic functions. Utilizing the properties of the analytic function, it becomes possible to differentiate ω with respect to ξ and singular points on ω-plane can be found where ω means frequency and ξ does wave number. Singular points for LOVE waves were already obtained numerically in the previous paper by the author. When ω is an analytic function, U=dω/dξ is also analytic. Singular points on ω-plane coincide to each other for ξ as well as for U.
If there is no condition other than the characteristic equation, no relation can be found between ω and ξ. In order to avoid this defect, it is often assumed that the imaginary part of ω is zero. In the present paper, however, another condition is proposed in which the imaginary part of dω/dξ is to be zero. Wave groups are usually defined by the present condition which gives saddle points on ω-plane.

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On the Anomaly of Travel-Time of S Waves Observed in Eastern Japan

Part I

Soichi HISAMOTO

1965 Volume 18 Issue 3 Pages 142-153
Published: September 25, 1965
Released on J-STAGE: March 11, 2010

DOIhttps://doi.org/10.4294/zisin1948.18.3_142

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In Eastern Japan, travel time of S wave usually shows remarkable anomaly. Neither mis-locations of the hypocenters nor mis-readings of the onsets of P and S waves are found to be the cause of this phenomenon. We cannot but believe that such an anomalous phenomenon actually exists.

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Heat Flow from Earth's Mantle and Tectogenesis

Yoshiteru KONO

1965 Volume 18 Issue 3 Pages 154-168
Published: September 25, 1965
Released on J-STAGE: March 11, 2010

DOIhttps://doi.org/10.4294/zisin1948.18.3_154

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Heat flow from the earth's mantle toward the crust (Moho heat flow) is the main energy source of tectogenesis. During the active stage of tectogenesis, it should be several times greater than the normal value during the calm stage. A thermal coupling between the crust and upper mantle is studied.
Secular variations of temperature distribution and of surface heat flow of the crust are numerically calculated for various models of the Moho heat flow and crustal structure.
It is concluded that: (1) The temperature distribution within the crust is varied not only by the maximum value of the Moho heat flow and the crustal structure, but is considerably affected by a pattern of the Moho heat flow: (2) The maximum temperature attained within the crust is nearly proportional to the total heat given from the mantle: (3) To melt the crustal materials, superposition of effects of crustal thickening and of an increase of the Moho heat flow is preferable: (4) Judging from its thermal influence to the crust, the size of mantle convection, if it is existed, might be several hundred kilometers.

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A Paradox of the Tsunami (II)

Hisashi MIYOSHI

1965 Volume 18 Issue 3 Pages 169-170
Published: September 25, 1965
Released on J-STAGE: March 11, 2010

DOIhttps://doi.org/10.4294/zisin1948.18.3_169

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The Anomaly of wells before the Nankaido-Earthquake

Sadao MIYAMOTO

1965 Volume 18 Issue 3 Pages 170-171
Published: September 25, 1965
Released on J-STAGE: March 11, 2010

DOIhttps://doi.org/10.4294/zisin1948.18.3_170

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