PRELIMINARY TREMOR OF EARTHQUAKE MOTION. 153 



epiceutre) of an earthquake, is a problem which is very difficult 

 to solve. But I believe such must, in some cases, be approxi- 

 mately true. The following are some of my own observations 

 relating to the point in question. 



8. On the 8th November, 1894, at 8.25 p. m., I experi- 

 enced one of the after-shocks of the destructive Shonai Earth- 

 quake in tlie town of Fujishima, which is situated quite near 

 to the epicentre of that earthquake. At the time, I was sitting 

 quietly upstairs of a w^ooden two-storied house, and felt the 

 shock as a sudden blow coming from below, accompanied by a 

 loud noise, such as that caused by the falling of a heavy body 

 on the ground. The motion consisted of a single principal 

 vertical movement, followed by very feeble vibrations, the 

 whole duration being about 30 seconds. Although the effect of 

 the shock Avas strong enough to cause people to run out of 

 doors, I observed the lamps suspended from the ceiling of my 

 room remaining still and not thrown into oscillations. In this 

 case, the shaking began abruptly and had no preliminary tremor, 

 the origin of disturbance, which was evidently local, being 

 quite near to the place of observation. 



9. The observation at Midori. Soon after the great Mino- 

 Owari Earthquake of the 28th October, 1891, a temporary seis- 

 mological observatory was established at the village of Midori 

 in the Neo -Valley, before referred to (§ 1), and a number of 

 the after-shocks were seismographically registered. 



It is to be noted that after the initial great earthquake the 

 principal centre of seismic activity was not in the Néo-Valley, 

 but to the south of it in the vicinity of Gifu. The phenomena 

 of earthquake-sounds were, hewever, most frequent and intense 

 in the Valley, the sounds being usually like that caused by the 



