ON THE VOLCANIC PHENOMENA OF JAPAN. 



417 



Total 482 



The total area of ground disturbed each month is shown in the 

 following table, which may therefore be regarded as an approximate 

 measure of the intensity of seismic action each month : 



Square miles 



January . 60,000 ) 



February . 101,000 1 Spring 205,000. 



March . 44,000) 



April . . 28,000 



May . . 62,000 Summer 184,000. 



June . . 94,000, 



Cold Months 

 Warm Months 



Total . 



July . 



August 



September 



October 



November 



December 



Autumn 178,000. 



Square miles 



55,000 



36,000 



87,000 



, 13,000 



25,000 Winter 107,000. 

 69,000, 



312,000 

 362,000 



674,000 



Disturbances shaking more than 30,000 square miles 



„ 18,000 



2 



6 



13 



9 



12 



17 



24 



27 



63 



319 



Total . 492 

 The largest shock disturbed a land area of 34,700 square miles. 



Out of the 492 shocks 279 originated beneath the sea or near the sea- 

 shore. The district most shaken is the alluvial plain near Tedo (Tokio). 

 The eastern and southern part of Japan, or that portion of the country 

 facing the Pacific Ocean, is shaken very much more than the western side 

 facing the Japan Sea. The northern half of the empire, that is to say 

 the country north of Tokio, is shaken very much more than the southern 

 half. 



In Kiushin, where volcanoes are numerous, earthquakes have not 

 been so frequent as near the province of Kii, where there are no volcanoes. 

 In two instances volcanoes and earthquakes appear to be related. Thus 

 the earthquakes at the southern end of Satsuma occur at or near the 

 volcanoes of that district, while the shocks at the north-east extremity of 

 Honshiu occur at or near Osori-san. In the former district there were 9, 

 and in the latter 24 local shocks recorded. 



In the centre of Honshiu, near to Tokio, volcanoes are very numerous, 

 and it is in this part of the empire that there is the greatest seismic 

 activity, and it may also be added, abundant evidence of recent elevation. 



1886. E B 



