298 MIDDLEM1SS : KANGRA EARTHQUAKE. 



giving times from 

 Dehra Dun to : 



M. S. 



Barrackpur ...... 5-3 



Kodaikanal 10.22 



Toungoo 9-25 



VII. — On the time of transmission derived from the times given in the preceding 



pages. 

 Assuming that the origin of the seismic wave was in latitude 32-0-0, longitude 

 77-0-0, the distances on the arc are — 

 Origin to ; 



Dehra Dun . . . 131 miles = 211 kilom. 



Barrackpur . . . 944 „ =1,519 



Kodaikanal . . . 1,498 „ =2,411 



Toungoo . . . 1,512 „ =2,433 



and Dehra Dun being close to the origin, the differences between distances Dehra 

 Dun and the other observatories will closely approximate to the correct distances 

 along the great circles from the origin to those observatories. 

 The velocities of transmission found are — 

 M. s. ' 2*7 miles per sec. 



(5-3) Dehra Dun — Barrackpur 

 (10-22) Dehra Dun— Kodaikanal 

 (U-25) Dehra Dun — Toungoo . 

 or a mean velocity of 



) 



4-3 kilom. 

 2-2 miles 



.r 



C3-9 



.r 



C3-! 



•5 kilom. 

 2-4 miles 



kilom. 

 2-4 miles 



•9 kilom. „ „ 



It follows from this that magnetographs do. not register preliminary tremors 

 error so close as 200 miles to the origin. 



This velocity is intermediate between Prof. Omori's v 3 (4-6) and Vf> the sur- 

 face velocity 3-3 kilometres per second derived from the observation of a number 

 of earthquakes. 



Applying this velocity to the distances Dehra Dun to assumed origin we get — 

 Time of earthquake at origin 6h. 11m . 38s. — 55s. 



= oh. 10m. 43s. 



With reference to this Prof. Omori 1 writes : — 



" Thus the time of earthquake disturbance as registered by the magnetograph 

 at Dehra Dun was Oh. 50m. 38s. G. M. T., the approximate distance of that place 



1 Publications or Earthquake Investigation Committee in Foreign Languages, No. 24. 



