392 



L. MARTIN — ALASKAN EARTHQUAKES OE 1899 



Cape Whitshed; or (h) the determinations of local time by Professor 

 Gwillim and Judge Myers are in slight error, and in each case the ob- 

 served time comes, suspiciously, on an even five minutes; or (c) the 

 chronometer at the Coast Survey camp was not exactly right; or (d) 

 there may have been a complex of synchronous origins at other places 

 in the mountains beside Disenchantment Bay. One of the first two ex- 

 planations is believed to account for the discrepancies. The whole mat- 

 ter is stated thus fully in order to show the futility of any attempt at 

 closer computations based upon the local records at hand. 



The speed of transmission for a longer distance, Yakutat Bay to Vic- 

 toria, British Columbia, is as follows, taking the data from the shock of 

 September 3: Disenchantment Bay, latitude 59° 58' 20" north; longi- 

 tude 139° 33' west; Victoria, latitude 48° 23' north; longitude 123° 

 19' west. Distance in miles along surface (computed from an 18-inch 

 globe), about 1,000 miles. Time at origin. Oh. 21m. 40s., Greenwich 

 mean time; time at Victoria, Oh. 35m. 9s., Greenwich mean time. In- 

 terval for transmission, 13 minutes and 29 seconds, or 809 seconds; 

 1,000 miles in 809 seconds gives a speed of 1.23 miles, or 2.1 kilometers, 

 per second. 



The rate at which the earthquake tremors moved for greater distances 

 is shown in the following table, which is based upon computations by 

 Prof. John Milne^^^ on the assumption of an origin in the ocean west of 

 Yakutat, and therefore subject to a slight error. 



Speed of large Waves of Three of the Yakutat Bay Earthquakes, in Kilometers per 



Second. 



From Milne's assumed 



origin, southwest of 



Yakutat to— 



September 3 

 (Shide No. 333). 



September 10 



(Shide No. 337), 



early shock. 



September 10 

 (Shide No. 338), 

 the great earth- 

 quake. 



Victoria 









Toronto 



3.4 







Mexico 



2.3 

 2.7 

 3.1 

 3.6 

 2.9 

 3.5 



2.7 



Shide 



3.2 

 3.1 

 3.6 



2.9 



San Fernando 



3.1 



Bombay 



3.4 



Batavia 



2.3 



Cape Town 



3.4 



3.7 







Average speed 



3.3 



3.0 



3.0 



Average speed of all 17 observations, with origin assumed by Professor Milne, 

 3.1 kilometers, or almost 2 miles per second. 



103 Fifth Report on Seismological Investigations of the British Association for the Ad- 

 vancement of Science, 1900, plate iii, opposite p. 77. 



