The transmission of mechanical forces of the magnetic field through the top layers of the core into mantle is studied. It is shown that moderate fluctuations of the toroidal field near the boundary of the core are large enough to produce the observed variations in the rate of rotation of the mantle. A simple theoretical analysis of the motions near the boundary of the core shows that the equations of the geostrophic wind in meteorology can be applied to the layer.
In this paper, the occurrence of earthquakes is regarded as a stochastic process and to it the theory of stochastic process is applied with an intention to investigate the possibility of the earthquake predictions by this procedure. At first the theory of prediction is roughly sketched. Discussions follow as to what quantity in the phenomena should be taken as the stochastic variable. As the result [n(t)-E(n(t))] is found to be the most appropriate quantity, where n(t) is the number of earthquakes belonging to specified range of magnitude which occurred in a specified area from t=0 to t=t and E(n(t)) is the average of n(t) at t=t. The theory is applied to conspicuous earthquakes occurred near Shiriyasaid between 1900 and 1945, and the occurrence is predicted or extrapolated up to 1947 and compared with the actual.