538 



Dt'. C. Davison — British Earthquakes. 



The curves in Fig. 2 represent isoseismal lines of intensities 

 5 and 4. The former curve, which is the less accurately drawn 

 of the two, is 38| miles long, 22 miles wide, and 670 square miles 

 in area. Its centre is situated 4 miles N. 10° E. of Strontian, and 

 its longer axis rims from E. 36° N. to W. 36° S. The isoseismal 4 

 is 49 miles long, 31 miles wide, and contains 1,180 square miles. 

 Its longer axis is parallel to that of the isoseismal 5 ; the distance 

 between the two curves, as drawn, being 5 miles towards the north- 

 west and 4 miles towards the south-east. Outside this isoseismal, 

 the sound was heard at Kiniochhourn, Roy Bridge, and Fasnacloich, 

 the shock being also felt at the last-named place. All three places 

 ai'e 4 miles from tlie isoseismal, and lie respectively towards the 

 north, east, and south-east. 



Fig. 2.— Diagmm Map of the Stroutiau Earthquake: Oct. 14, 1902. 



The shock consisted of a single series of vibrations, which 

 increased in intensity and then died away, the average duration 

 of the movement being 3 seconds. 



The sound was heard by 98 per cent, of the observers. It was 

 compared to a passing train or heavy vehicle in 43 per cent, of 

 the records, to tlmnder in 43, wind in 3, and to miscellaneous 

 sounds in 11 per cent. The beginning of the sound preceded that 

 of the shock in 71 per cent, of the records, and coincided with it 

 in 29 per cent. ; while the end of the sound coincided with that 



