36 



MIDDLEM1SS : KANGRA EARTHQUAKE. 



Using this value for a in the general formula 



a 





f 



4 * 2 a 



where t is the period of the wave and v the maximum velocity of the 

 earth particle, we can obtain values of t and v. We thus have alto- 

 gether : — 



Acceleration /== 13 ft. per sec per sec 



Amplitude a as 9f inches. 



Velocity # = 3i ft. per second. 



Period t = 1 * seconds. 



On the other hand, by using Prof. Omori's second formula for the 

 case of a pillar overturned in the forward direction when the period of 

 motion is comparatively long, and applying it to the second of the pair 

 of gate-pillars overturned away from the direction of shock, we get :— 



y8g y {l—cos ») 

 3 cos 2 $ 

 where $ is the angle between a vertical side and the diagonal of the 

 pillar. That is : — 



v& 3*87 ft. per second, 

 a value which is sufficiently near the one previously obtained by the 

 other method to be corroborative of it 



In the same cemetery also a large flat slab, 4 ft. 10 in. by 2 ft. 

 and 4 in. thick had moved 4 in. towards N. 60° E. (Fig. 14.) 



PLAN 



N60E 



SECTION 



Fig. 14. 



