Journal of Physics of the Earth
Online ISSN : 1884-2305
Print ISSN : 0022-3743
ISSN-L : 0022-3743
Volume 37, Issue 5
Displaying 1-4 of 4 articles from this issue
  • Tsuneji RIKITAKE, Ryosuke SATO
    1989 Volume 37 Issue 5 Pages 303-311
    Published: 1989
    Released on J-STAGE: April 30, 2009
    JOURNAL FREE ACCESS
    That some volume of magma could be squeezed up from the magma reservoir triggering a volcanic eruption when compressional tectonic stress is strengthened by plate motion has been proposed as a possible explanation of successive occurrences of volcanic eruption and large earthquake. This idea, called the "flask model, " has been put forward in attempting to account for the relationship between the activities of Izu-Oshima volcano and the occurrences of great inter-plate earthquake associated with the Sagami trough off the Pacific coast of Central Japan. It is intended in this paper to examine whether such a model really works or not by taking the detailed configuration of magma reservoir into account. When a combination of parameter values usually accepted is assumed, it turns out that the volume of magma squeezed up by compressional tectonic stress may not be enough for triggering an eruption. It is therefore doubtful that a flask-model mechanism is actually working. Occasional eruptive activities of the volcano may rather be due to an increase in internal gas pressure in association with development of chemical reaction in the magma reservoir.
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  • Susumu NISHIMUR, Tomohiro HORINOUCHI
    1989 Volume 37 Issue 5 Pages 313-323
    Published: 1989
    Released on J-STAGE: April 30, 2009
    JOURNAL FREE ACCESS
    The quartz-inclusion method, which has been developed in the thermoluminescence dating of pottery, was applied to date some fault-crushed materials. In dating these samples, the blue and the infrared absorption filter were used. The seven samples of fault-crushed materials were collected from the areas along the Arima-Takatsuki tectonic line and the Yamasaki fault, Southwest Japan. Their thermoluminescence ages, which indicated the time of last heating over 230° of faulting, were dated, and the accuracy of thermoluminescence dating of faultcrushed materials was examined.
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  • Jeen-Hwa WANG, Francis Ta Wu
    1989 Volume 37 Issue 5 Pages 325-343
    Published: 1989
    Released on J-STAGE: April 30, 2009
    JOURNAL FREE ACCESS
    Finite difference technique is applied to study Rayleigh wave propagation in laterally inhomogeneous media. The surface Rayleigh wave particle motion trajectory is studied to be a parameter to show the effect caused by lateral inhomogeneity. Computed results show that the trajectory is very sensitive to the presence of lateral inhomogeneity in at least three ways: change of peak amplitude, change of propagation velocity, and inclination of particle motion trajectory. The inclination of particle motion trajectory is particularly sensitive to the presence of lateral velocity variations, and is mainly at the nodes near the discontinuity within half the characteristic wavelength. The models with vertical discontinuity produce more effect on the Rayleigh wave particle motion than the models with inclined discontinuity.
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  • Masatsugu OOE
    1989 Volume 37 Issue 5 Pages 345-355
    Published: 1989
    Released on J-STAGE: April 30, 2009
    JOURNAL FREE ACCESS
    We investigate effects of the configuration and the bathymetry of the oceans on the tidal dissipation of the Earth's rotation. Discrete tidal equations with linear dissipation terms are solved for M2 ocean tide using present oceans and a Permian ocean. Model properties are also examined through simulation studies by changing parameters related with the bottom friction and the eddy viscosity. These studies show that M2 ocean tide explains for the most part the tidal dissipation of Earth's rotation and it seems that there is a tendency that the tidal dissipation was slightly smaller in the Permian era than in the present age.
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