It is well-known that the focal depth of an earthquake can be precisely estimated by the travel time of earthquake waves observed near the antipodes, if the time of occurrence at the focus be known. For this object, we attempted to get a table of accurate travel times of the P1' wave near the antipodes (>145°) from the observational data of the New Zealand earthquake (1929, VI 16) which was precisely investigated by Miss Lehmann (Gerl. Beit. z. Geo. Bd. 26, S. 402.) The result obtained is shown in Table III, which can be used for normal as well as deep-focus earthquakes. The values in this table are in a good coincidence with the results obtained by the observation of the deep-focus earthquake (1931, II 20) occurred in the North Japan Sea.
In the present paper the author investigated the ScS waves of deep earthquakes occurred in Japan, and constructed their time-distance curves especially for the earthquakes of very small epicentral distances. The depth of the Earth's core from the surface was reexamined, and a method was devised to evaluate the epicentral distance and the focal depth of a deep earthquake from the readings of ScS_??_P and S_??_P at a single station. Also the author studied a peculiar appearance of the initial phases of the S wave of deep earthquakes.
Recently it was found by Messrs. K. Kadoya, S. Hidaka and M. Miyamoto that the ScS wave appeared very conspicuously in the seismograms of deep-focus earthquakes recorded at various stations near the epicenter. In this paper, the author intends to get a table of travel time curves of this ScS wave for earthquakes of various focal depths. For this purpose, first the depth of the Earth's core is obtained by using the arrival times of the ScS waves observed in the case of the deep-focus earthquake (1932, XI 13) whose position of epicenter, focal depth and the time of occurrence can be accurately known. This depth was obtained to be 2900 km. or a little larger, and the depth of 2900 km. hitherto generally accepted by seismologists is reassured. Then using the values of velocities of the S waves in the crust obtained by us (Geophysical Magazine. Vol. VII, No.1, No.2 and No.3), the travel times of the ScS wave are fully calculated and the results obtained is given in Table 5. When the phases of P, S and ScS all appear distinctly in the seismograms taken at a station near the epicenter, the focal depth of this earthquake and the epicentral distance of that place can be determined by the differences of arrival times, S-P and, ScS-P. Table 6 shows the relation between H, and S-P, ScS-P. Tables 5 and 6 may be conveniently used for the investigation of near earthquakes.
Sanaru-ko is a highly eutrophied brackish lake, 0.6km. in width and 22km. in length, situated near the City Hamamatu in the prefecture Siduoka. Almost all the quantities of Hypomesus olidus (Pall.), Konosirus punctatus (T. & S.) and other fishes died in the short period, from the evening of 30th, to the morning of 31st., August 1933. In this paper the causes of this sudden occurrence were investigated by us in view of chemical, biological and meteorological conditions. Since the middle part of the month of August a remarkable outburst of water-bloom, mainly consisting of Clathrocystis aeruginosa Henfrey had been occurred and before a few days of this unusual event the phytoplankton died and sunk down into the bottom layer. As a result of putrefaction of the organisms the O2-consumption and H2S-production (3mg./L) were made and moreover the supply of O2 was very poor by the prevalence of the calm weather.
In this paper the relation between the yield of rice-crop and the summer temperature has been determined for each prefecture of Japan. The average yield of rice-crop in each district correlates to the normal summer temperature of the prefecture, and its correlation coefficient was found to be 0.54. The variability of the yield of rice-crop for the twenty years preceeding 1931 and that of the summer temperature were calculated. The ratio of these two quantities depends upon the position of each prefecture, and the average value of these ratios for the whole country is about 50%.
Formulas of different types for use in minimum temperature forecasting have been proposed by many authors. It is well known that the morning minimum temperature is function of several variables, but the effect of some of them is obscure, so there are difficulties in the way of applying formulas in actual practice. In this paper, the present author further studied the hygrometric formula which was proposed by Ellison and others, and using the data observed on frosty night at Gihu, obtained the equation of the first degree as an empirical formula. Applying the formula above obtained in actual practice, keeping in mind the result of the investigation on the moisture of the earth surface, the state and the path of high, which causes a frost damage, he drew out a satisfactory result. Also he classified the investigations in our country according Ellison's classification and discussed its applicability to the Gihu district. And also, following Ängstrom's treatment, here a conclusion is drawn that the law of Kammerman comes to naught at Gihu.