EARTHQUAKE MEASUKEMEN'Tö OF RECENT YEARS. 71 



The ratio of the max. h. in. in Iltjngo to tli:ir of liitotaiibasihi 1:8 



J) 5) 35 35 5? ^* ^^" 33 33 3» 33 33 33 io:io 



,, ,, ,, ,, ,, V. m. to mnx. li. ni. in Hitotsuhashi 1:12 



J? 33 33 33 33 33 33 53 33 33 33 33 IlOHgO 1:0 



No. 95. — Tokyo was on tlic edo;e of the disturbed area. 'J'here 

 were a ï^^w distinct \ ertieal wa\'e.s at Hitotsubashi. 



Summary of Results. 



The results obtained iVom n study of tlic ])reeedin;jf lable in:iy 

 be summarised as folh)ws. 



In most of the earthquakes vertical motion did not aj^pcar, tliat 

 is, the ground moved entirely in a horizontal plane. This was on 

 account of the origin of the disturbance being far away ïvoxn the 

 observing station. In the above table, if we reject the slight shocks 

 marked trcvior, and the doubtfid cases, we see that out of 100 earth- 

 quakes vertical moti(3n occurred in 28 only, /. 6'., once in 3"() shocks. 



Taking a^•erages of all the quantities in^•olved in these 28 cases, 

 we find : — 



Maximum horizontal motion 1*2 m.m. 



Complete period of maximum horizontal motion .... 1 sec. 



Duration of horizontal motion 12-1 sec. 



Maximum vertical motion 0'18 m.ni. 



Complete period of maximum \ertical motion 0*56 sec. 



Duration of vertical motion ■12 sec. 



Treating similarly the horizontal motions in 05 earthquakes 

 recorded at Hitotsubashi (soft soil), we find : — 



Maximum horizontal motion 0*73 m.m. 



Complete period of maximum horizontal motion ... 0*76 sec. 

 Duration of horizontal motion 117 sec. • 



