36 



Symposium on Microseisms 



from this source and Pasadena and Honolulu 

 do not in this case, there is additional support 

 for the idea advanced earlier than the Cen- 

 tral Valley of California and the ocean basin, 

 in this case the North Pacific, absorbs these 

 microseisms. 



It should be noted that conclusions reached 

 in this section imply only that the North Amer- 

 ican continent, with one or two exceptions, is a 

 good transmitter of microseisms and that the 



adjoining ocean basins are not; and except at 

 the very first, the period does not increase with 

 distance. No inference as to source or source 

 mechanics was made except that the location 

 was in a general area near one coast or the 

 other. 



The relationship of these and other se- 

 lected microseisms to weather conditions will 

 now be presented. 



Case I. On January 15, 1950, a violent 







Figure 4. Weather charts 19-21 December 19 50 showing a storm moving off the coast of northeast 

 North America and microseisms recorded at Chicago during this time. In this and other illus- 

 trations, the flags show wind velocity in 10 knot intervals and the numerals represent days, 



hours and minutes. Isobar interval is 5 millibars. 



