TIMES OF YAKUTAT BAY EARTHQUAKES 



393 



Professor Milne has also shown that the time necessary for one of 

 these shocks (September 3) to traverse the earth^s circumference or two 

 diameters slightly exceeds 210 minutes. ^°* This is a rate of about 1.9 

 miles, or 3.0 kilometers, per second. Doctor Omori made a similar cal- 

 culation for the September 10th waves/*^^ which traveled around the 

 earth with a velocity of 3.6 kilometers per second. 



Prof. C. G. Knott^^^ has anah^zed the relationship of speed of trans- 

 mission to the location of the paths of the three chief Yakutat Bay earth- 

 quakes as follows, on the assumption that the path is not along the chord, 

 but more approximately along the arc. The paths lie as follows : 



Victoria Under sea. 



Toronto Half sea, half land. 



Mexico Half sea, half land. 



Shide Mostly sea, polar archipelago, Greenland? 



San Fernando Half sea and land, largely polar. 



Bombay Mostly land — Siberia, Tibet. 



Batavia Deep sea, east of Asia. 



Mauritius Siberia, India, Indian Ocean. 



Cape of Good Hope Polar sea, Europe, Africa. 



Still assuming what we know now to be a slightly erroneous origin 

 and assuming constant speed for small distances and with nine minutes 

 as the time from the origin to Victoria, he made the following table : 





Chord. 



Time of passage 



in 



minutes. 



Speed. 



Arc. 



Arc degrees. 



Chord. 



Arc radians. 





iMin. 



Min. 



Min. 



Victoria 16° 



Toronto 40° 



Mexico 49° 



Shide 70° 



San Fernando. 77° 

 Bombay 105° 



Batavia 108° 



Mauritius 145° 



Cape of Good 

 Hope 165° 



.28 



.68 



.83 



1.15 



1.25 



1.59 



1.62 



1.91 



1.98 



9 00 00 

 22 22 22 

 00 29 28 

 39 42 41 

 44 44 44 

 55 55 57 



00 65 75 



90 00 88 



88 89 83 



1 

 1 



1 

 1 

 1 

 1 



{\ 



1 

 1 



8 



8 



7 



8 



75 



9 



66 \ 



44/ 



63 



9 



.031 

 .31 

 .29 

 .29 



.28 

 .28 



.23 



.215 



.226 



.031 



.31 



.30 



.31 



.305 



.33 



.284 

 .33 



-r ,, , ^ ,, chord , arc radians -, , -, , kilom. , - . 



In the above table — -. — and -. may be reduced to by multi- 



mm. mm. "^ sec. 



1 • r. T n^ ^^c degrees , , , , kilom. , i^- i • x. -, o^ 



plymg by 1.06; ~ may be reduced to by multiplymg by 1 84. 



tion 



1903 



tlon 



L 



Fifth Report of Committee on Seismological Investigations of the British Associa- 



for the Advancement of Science, 1900, p. 69. 



Publications of Earthquake Investigation Committee in foreign languages, no. 13, 



, pp. 121-124. 



Fifth Report of Committee on Seismological Investigations of the British Associa- 



for the Advancemeent of Science, 1900, p. 77. 



XXVIII — Bull. Geol. See. Am., Vol. 21, 1909 



