334 MIDDLEMISS KANGRA EARTHQUAKE. 



long axis. The only difficulty is the recognising of that portion of 

 the cross -section where the intensity declines or varies most rapidly. 

 With regard to the Kangra end of the northern epicentral tract, there 

 is no difficulty, as has already been shown, in making a selection of 

 points situated near its W.N.W. end which must be correct within a 

 few miles. From those points the distance to the ep'icentral line cannot 

 be less than 7 or more than 12 miles. The centre, therefore, between 

 Kangra and Dharmsala must lie at some depth greater than 7^/3 and 

 less than 12^3 miles, i.e., between about 12 and 21 miles. Taking 

 another cross-section over the tract from Naggar through Sultanpur, 

 Mandi, and Suket, the horizontal measurements, though less exact, 

 cannot be less than 12 or greater than 24 miles, and therefore the 

 depth must lie between 12\/3 and 24^3, or between 21 and 40 miles. 



The centrum thus deduced for this part of the earthquake-area can, 

 therefore, be represented by a line or axis running 



Pitch ot centrum. . . 



from a point about midway between Kangra and 

 Dharmsala in an E.S.E. direction towards Bajaura, a distance horizontally 

 of 50 miles and at a depth of from>12<21 to >21<40 miles, the average 

 being from 16 to about 20 miles, with a dip or pitch of 13 J degrees 

 with the horizontal. 



It will no doubt be thought bv many that the above depths are pos- 

 sibly exaggerated, and in any case there is no doubt about their vague- 

 ness. Whilst freely admitting the possibility of serious refraction caused 

 by change of rock -formation through which the shock must have been 

 propagated, there are two general facts which point to at least a 

 considerable depth for the part of the centrum below the Kulu area. 

 One is the extremely large area over which the shock has undoubtedly 

 been felt, and the other the only moderate violence at the surface. 

 In other words, a shock of intensity 8 at the surface at Kulu, if of 

 shallow origin, would not have been so powerful at that origin as 

 to have been felt in such remote parts as the Bombay Presidency and 

 Assam, nor would one of intensity 10 at Kangra unless it also were 

 proportionately deep-seated. 



