The following two phenomenon observed at Kakioka magnetic observatory from Aug. 1932 to Apr. 1933 are reported; i) Micro-pulsation and Storm of earth-current ii) Some variations of earth curr. which may be caused by earthquakes. The former points out that micro-pulsation and storm are also observed in earth-curr. as well as in earth-magnetism, showing a closed relation, even if their appraent features are so markedly different. The later shows a possible relation between earth-quake and earth-curr., but a basted opinion must be avoided. One of the most desirable method in this line is to study each record refered to those at other places and of other related phenomenon, especially of earth-magnetism.
This report is intended to give a complete table of travel times of earthquake waves such as P, S pP, PP, sS, SS, etc. especially taking the depth of focus into account. The calculation for the present table is based upon the results already obtained by us in the previous investigations on both near and distant earthquakes, whose epicente. s lie near the Japanese Islands. (Vol. 10, No.8, p. 460-474 and Vol. 11, No.1, p. 14-28 of this journal). This report is only a summarized one and the full text will be published in the Geophysical Magazine in the near future.
Here the authors made a consideration on the method of tracing the path of propagation of tunamis caused by earthquakes. The differential equation of the path was obtained for the case in which the position of the observing station and that of the epicentre of the earthquake are given. As an example of solution of the differential equation, a particular case was treated in which the profile curve of the bottom surface of the sea is a parabola. The path thus obtained is a circular arc. This method was applied to an actual case. The result suggests its applicabihty to some other similar cases.
In this paper, we calculated the travel time of the transverse waves reflected at the boundary of the earth's nucleus situated at the depth of 2900 km. using the velocities of the seismic waves obtained by B. Gutenberg and compared this with the ScS phase revealed on the seismograms of some deep focus earthequakes. Thus we drew the conclusion that the velocities shown by Gutenberg seem to be a little too great in the earth crust.