ON THE EARTHQUAKE AND VOLCANIC PHENOMENA OF JAPAN. 101 



Thus, of 101 earthquakes, 69 were horizontal, 11 were a combination 

 of horizontal and vertical, and 21 were not definite, being very feeble. 

 The number of slow earthquakes exceeded that of rapid ones by 13, while 

 46 were so feeble that it was difficult to determine their period of 

 vibration. 



II. Earthquakes in 1889. 



In 1 889 the number of disturbances recorded in the Empire was 930. 

 The great increase in the number of disturbances this year was due to the 

 number of small shocks which succeeded the great earthquake of Kuma- 

 moto, which I described in the tenth Report (1890). The great earth- 

 quake took place on July 28, and on the 29th and 30th 62 shocks were 

 recorded. Subsequently the exact time of occurrence of 281 disturbances 

 was noted. The total number of shocks following the great earthquake 

 was therefore 343, and the total for the Empire, 992. As in previous years, 

 certain parts of the western side of Japan appear to have been free from 

 earthquakes. 



1. Number of Earthquakes in each Season. 



The number of earthquakes observed every month from January to 

 December 1889 is given in the following table : — 



From the above table it will be seen that we have the maximum fre- 

 quency in August, and the minimum in June. The general increase in 

 frequency is due to repeated shocks after the terrible earthquake in 

 Hiogo already referred to. 



The frequency in each season may be deduced from the above table ; 

 thus : — 



