70 



s. SEKIYA 



No. 77. — It was quite a strong shock nearer its origin which was 

 in the sea not far from the shore. The maximum vertical motion 

 arrived several seconds before the maximum horizontal motion. 



No. 83. — A^ertical motion was comparatively large considering 

 the smallness of the horizontal motion ; moreover it was clearly pro- 

 nounced exhibiting eight distinct waves. Its maximum appeared 

 a few seconds after the horizontal maximum. 



No. 8Ô. — This is one of the two largest earthquakes in 1887. 

 The origin of the shock was in SW about 35 miles from the Observa- 

 tory. The seismic waves propagated nearly 200 miles to the west 

 and north-east along the Pacific sea-board. On the north-west they 

 approached to the shores of the Japan Sea. They shook, in all, about 

 82,000 square miles of land area. 



At Hitotsubashi, after few seconds from the commencement of 

 the shock the o-round moved suddenly 3 m.jn. toward the west. At 

 the thirtieth second the maximum horizontal motion recorded in the 

 Table was observed, which apparently corresponded with the 

 maximum horizontal motion in Honml. More than sixty distinct 

 shocks were recorded. 



At Hongö, the earthquake commenced with quick tremors. 

 During the third second there appeared for the first time a vigorous 

 horizontal motion in NW and SE (i. e. at riofht anodes to the line 

 joining the origin of the disturbance and the Observatory) accompanied 

 by a consideral)le vertical displacement. The maximum vertical 

 motion occurred at the ninth second. The maxinuiin horizontal 

 motion occurred at the thirty-third second. 



Decided vertical and horizontal motions simultaneously occurred 

 at the second second. See Plate XXVI, Vol. I of this Journal. 



