68 s. SEKIYA 



motion occurred 6 .seconds from tlie commencement sind the maxi- 

 mum vertical motion 2 seconds later. Several distinct verHcnl waves 

 of the average period of 0'3 seconds were registered. 



No. 39. — Trace of the vertical motion was visible though the 

 shock was only local and the motion small. 



No. 41. — The whole of North Japan was disturbed by this sliock, 

 tlie observing station being near the southern extremity (^f the dis- 

 turbed district. 



No. 47. — The origin which was inland was comparatively near 

 the city. There were hardly any vertical tremors during the first few 

 seconds while there were considerable horizontal tremors. A decided 

 horizontal motion occurred at the beginning of the sixth second ; more 

 pronounced vertical motion began one and half seconds later and its 

 maximum ocurred several seconds after. See l^late IX, Vol. \ <^f 

 this Journal. 



No. 50. — This was another large earthquake in which the seismic 

 waves were propagated from the origin some 120 miles both north and 

 south, and 61 miles toward the west, where they were stc^pped by 

 the mountain. On the east they reached the Pacific Ocean. The 

 observing station was comparatively near the origin. 



This shock was preceded by tremors of quick period during the 

 first eight seconds, then there suddenly appeared the maximum 

 horizontal motion ; at this time tlie vertical motion, which was 

 visible from the beo-innino; was vet verv small — -0-0(S m.m. with a 

 period of 0"-l second ; afYer (î seconds it reaching the maximum, and 

 continued for eighty-five seconds with decreasing amplitudes and 

 with lengthening periods. The ratio of the vertical motion to that 

 of horizontal motion was 1 to 8'3 in amplitude, 1 to l'ö in period 

 and 1 to 2*2 in duration. 



