80 



REPORT — 1903. 



Out of sixteen deflections there are twelve instances where the 

 greater number of earthquakes have taken place during the deflection 

 period. In three instances the number for the deflection period, although 

 exceeded by number before or after that period, has been greater than 

 the average of the sum of the preceding and succeeding numbers. In 

 only one instance (February 5 to April 19, 1896) have the earthquakes 

 in the deflection period had a distinct minimum. The totals for before, 



+ 0-3 



+0-2 



+ 1 



0-00 



during, and after comparable deflection periods are respectively 117, 200, 

 and 153. 



One inference from this investigation is not that the molar displace- 

 ments accompanying large earthquakes result in polar displacements, but 

 rather that changes in direction of these latter movements, particularly 

 when the rate of change has been rapid, have had an influence upon 

 earthquake frequency. From Albrecht's figure of movements of the 

 North Pole (tig. 2), on which the numbers of large earthquakes correspond- 

 ing to difierent periods are given, the periods of rapid change can be seen. 



