Yearly Variations of Terrestrial Phenoraena and Solar Activities. 7 



II , however, it may be remarked (figs. 7 and 8) that the number 

 of minimum is of the type similar to Class I, while the number 

 of maximum shows a distribution proper to Class II, especially for 

 not very large value of jV+S. 



It must be remarked in passing that some stations show 

 anomalous behaviour in changing the class to which they belong, 

 by the choice whether the felt shocks only or the total numbers 

 are taken. For example, Tokyo belongs to Class IT for the total 

 frequency, but if the ' felt ' only is taken, it belongs to I. Again, 

 Maebasi and Aomori Avhich belong to Class I for the total 

 frequency, are transferred into Class II when the felt earthquakes 

 are taken. It will be seen later that these stations are near the 

 boundary of the areas separating the different classes. 



Plotting the stations of different types on a suitable map of 

 Japan (Fig. 9), we see that Class I and II shows a distinct geo- 

 graphical distribution, the latter class decidedly predominating on 

 the Japan Sea coast. The region belonging to Class II' appears 



Fig. 9. X : Class I. Q: Class II. 

 Zs : Class II . 



Fig. 10. Area dotted over shows maximum 

 frequency in summer, while the remaining 

 land area shows maxima in winter. (Corea 

 and Manchuria are excluded). 



