ON THE EARTHQUAKE AND VOLCANIC PHENOMENA OF JAPAN. 163 
and had a period of nearly 4 seconds. It shook 3,533 square ri, but only 
extended to lat. 37°N. 
The one at 6h. 42m. 36s. A.m., which lasted 64 minutes, and had a 
period of 3°4: seconds, extended to lat. 36°N., and shook 2,236 square ri. 
All these disturbances extended southwards to Owari. 
The Kumamoto Earthquake. 
During my absence in Europe, on July 28, 1889, at 11h. 40m. p.m., 
the whoie of Kiushiu, a portion of Shikoku, and the main island were 
disturbed by an earthquake of unusual severity. The land area shaken 
was 6,520 square ri, the most violent motion being on the western flanks 
of the volcano Mount Aso, which has a well-formed ring crater 7 to 12 
miles in diameter, with a smoking cone in the centre. 
Altogether some 114 shocks were felt, and subterranean roarings were 
heard 87 times. These disturbances oceurred between July 28 and 
August 13. The damage may be summed up as follows :— 
Hovses ruined . ; . 200 _ Persons injured - 74 
Houses shattered 4 <a 200 Bridges destroyed , =f) 
Persons killed . : SP aeAY, Bridges broken . 21 
At Oita, some 60 miles north of the district of greatest disturbance, a 
eismograph gave the following records :— 
Duration C : : . ° . m » 70 secs. 
Direction : ‘ f : ‘ ; A é . S&.S.W.-N.N.E. 
Maximum horizontal motion 2 : ~ - 12:4mm. 
Period . ° 4 ; 4 . 27 secs. 
he movement was gentle. 
EARTHQUAKES IN 1887. 
In my fourth report to the British Association, I gave an account of 
87 earthquakes which had occurred in North Japan between October 
881, and October 1883. In consequence of this work, the expenses of 
hich were partly defrayed by this Association, Mr. Arai Ikunosake, 
irector of the Meteorological Department, established some 600 post- 
rd stations throughout the empire with a view of making similar but 
ore extended observations. The results of these observations for 1886 
ere given in my eighth report, and the following is an epitome of the 
sults obtained for 1887. For purposes of comparison these latter have 
en combined with the results for 1885 and 1886. 
FREQUENCY OF EARTHQUAKES. 
4 
_ During the years 1885, 1886, and 1887, the numbers of earthquakes 
recorded in Japan were 482, 472, and 483, the numbers representing the 
ily average of shocks per day being 1°32, 1:29, and 1:32. The greatest 
number of shakings in 1887 occurred near 'l'okio, where 80 distinct 
P ocks were recorded, and some 30 or 40 miles to the north of Tokio, in 
hilachi, where 50 disturbances were noted. 
Distarmurion or Seismic Enerey. 
Speaking generally, the areas which are most frequently shaken are 
the same in successive years, the eastern side of the country being very 
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