Various types of energy released or consumed during the moon's evolution are analyzed and the energy balance of the moon is discussed. The total heat accumulated during the moon's evolution is about 1.8×10³⁶ ergs (assuming no heat escaped by thermal convection).
A linear stability problem for the moon's interior is considered. For appropriate values of physical parameters it is found that the moon's interior should be in a convective state. The internal temperature distribution in the presence of the convection current is given. The thermal convection within the moon prevents its internal temperature from reaching the melt temperature. The temperature within the convecting moon is about 1500°C at the center, and about 900°C at the 200-km depth. There are two types of temperature-depth profile within the moon, i.e.;(1)heat transfer by conduction above 400-km depth, and (2) heat transfer by convection below 400-km depth. The temperature gradient within the moon's convecting region differs very little from the adiabatic gradient.

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The most stable flow pattern responsible for a ridge transform fault system is studied based on a mantle model of a layered viscous fluid. If the How beneath the ridge is caused by a passive convection, the stable flow on the earth's surface is most likely perpendicular to the ridge axis only for components of small wavelength, less than about 5.5 times of the thickness of the lithosphere, and oblique to the ridge axis for long wave components. This difference may suggest the reason why transform faults are formed on every oceanic ridge. It is concluded that a very small viscosity in the asthenosphere and negligibly small resistances against sliding motion are required to maintain the system. It is also suggested that the amount of ridge offset depends not only on the lithosphere thickness but also on the total direction of the system with respect to the plate motion. From the characteristic feature of the equatorial mid-Atlantic ridge, the thickness of the viscous lithosphere is estimated to be about 30km or less under the rigid plate and the viscosity in the asthenosphere may be as small as one-hundredth of that in the lithosphere.

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When a chain-reaction-type fracture formation is postulated at a seismic source (OTSUKA, 1972), the seismic energy account turns out to be influenced by the activity of earthquakes with moderate magnitudes in contrast to the generally accepted idea that it is primarily controlled by the activity of major earthquakes.
While this current idea is needed to provide an independent explanation for the cut-off phenomenon of seismic energy for large earthquakes, the chain-reaction model demonstrates that it originates from the very nature of seismic phenomenon itself.

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The effect of hydrostatic confining pressure on compressive strength of crystalline rocks is investigated in some detail on the basis of the available published experimental data.
It is found that the pressure dependence of the compressive strength of rocks is same, in spite of different origins, for the same rock type and that there is no appreciable difference in the effect of confining pressure on compressive strength among diorite, diabase and peridotite, and among carbonate rocks. The quantitative relation of these facts to the bulk hardness of rock are discussed. A strong positive correlation was observed between the effect of pressure on compressive strength and the bulk hardness for silicate crystalline rocks.
If the relation between compressive strength C and confining pressure p is expressed with the empirical formula; C/C₀=1+K(p/C₀)n, where C₀ is the uniaxial compressive strength, then both K and n are found to be constants according to rock type. Then, a practical estimation of the compressive strength of a rock at any confining pressure can be made if only the uniaxial compressive strength of the rock is known, once the values of K and n for elach rock type are determined.

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A spectral analysis is made of records at Tsukuba station. The earth-quakes analyzed are located in Hokkaido and the Kuril Island. Almost all of their ray paths are in the seismic dipping zone of the island arc. The Q_α (Q for P wave) and Q_β (Q for S wave) are estimated graphically. It is shown that Q_β is much larger than Q_α in the frequency range 0.1 to 10Hz. The ratio of Q_β to Q_α is as large as 10. This is attributed to the weak attenuation of S waves in the dipping seismic zone. Comparison with the records at Urakawa, Sendai and Tsukuba indicates that short period waves are propagated without significant attenuation together with long period waves. This is also attributed to the weak attenuation of short period seismic waves in the dipping seismic zone. It is suggested that the earthquakes have spectral peaks at their source.

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Near field observations of seismic waves as well as static deformations are quite necessary for elucidating focal mechanisms, from which we can obtain many informations on dynamic process at the focus and stress field within crust or upper mantle.
When comparing theoretical seismograms with observed ones, it is sometimes sufficient to calculate seismograms on the basis of an assumption of a semi-infinite medium or even an infinite medium. However, in order to discuss detailed features of wave forms, it is of course required to take realistic structural model into account.
In this paper, theoretical expressions are derived for surface displacements in the near field due to an arbitrary oriented fault model in a multilayered medium. Numerical examples will be presented in the forthcoming paper.

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Premonitory change in the ratio of compressional to shear wave velocity, υ_p/υ_s was ascertained for two moderate size earthquakes which occurred at shallow depths in Japan. The anomalous periods preceding the earthquakes were about one year and three to four months for earthquakes of magnitudes 6.5 ahd 5.3, respectively. A similar phenomenon was also found for the Matsushiro Earthquake Swarm. Two large earthquakes located near the Japan Trench were also investigated. For those earthquakes, a post-earthquake decrease in υ_p/υ_s ratio was distinct, but forerunners were not confirmed. Appearance of premonitory change in υ_p/υ_s ratio may depend on the type of earthquake.

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