40 



Symposium on Microseisms 



11 



SitKa 



cma ga *~ 



52: 





^3el 



^45- 



MARCH 1952 



Figure 8. Microseisms recorded at Sitka and Chicago 11-13 March 1952 and weather charts 10-13 

 March 1952 showing successive northeast Pacific storms. Isobar interval about 7 millibars. The 

 storm centering over the Aleutian Islands at 12:30 10 March, shown upper right, is believed 

 responsible for the microseisms as illustrated, rather than the storm shown at left center 

 which followed two days later. Note that the first storm had abated by the time the microseisms 



had reached their peak. 



away. Yet two late August 1952 hurricanes 

 on the coast of the Carolinas or southward sent 

 microseisms as far as 1700 miles inland to 

 Bozeman, Mont. 



Referring to Figure 5 of Gilmore's paper 

 the amplitudes at Whiting Field are about the 

 same as at Jacksonville which is much closer 



to the storm center; and about twice the am- 

 plitude at Miami which is about the same dis- 

 tance as Whiting. The slightly greater ocean 

 path to Jacksonville about offsets the addition- 

 al land path to Whiting, but the somewhat 

 greater ocean path to Miami is not nearly 

 enough to compensate for the longer land path 

 to Whiting. 



