Amplitude Distribution of Storm Microseisms 



33 



addition, data from storms traveling in differ- 

 ent directions over different though intersecting 

 paths must be checked against one another, so 

 that if a storm is over any given point in the 

 ocean the amplitude ratios recorded at any two 

 stations used in the net must be the same 

 regardless of the direction of approach of the 

 storm to that point. Presumably this condition 

 has been met by the Microseismic Research 

 Project and if the method has been proven by 

 independent observers, there is little room for 

 adverse argument. 



Although Mr. Gilmore favors the idea that 

 storm microseisms which are recorded in force 

 on land are generated beneath the eye of the 

 storm, he nevertheless reports that the ampli- 

 tude relationships at the several stations will 

 hold regardless of how the microseisms are 

 generated. I concur with Mr. Gilmore only 

 up to a certain point. 



If the microseisms are generated on the 

 ocean bottom beneath the storm, then barring 

 extraneous sources, the amplitude ratios at two 

 stations should be about the same. 



Further if two storms approach a given 

 spot in the ocean from the same direction and 



the microseisms are caused as a result of the 

 fetch reaching the nearest shore, then ampli- 

 tude relationships should also hold. But if the 



Figure 1. Paths of 3 hurricanes; A, B, C, 



passing over point producing microseisms 



recorded at stations S. and S„. 



W.'./.'.'.s',' V t '■ aw.',' — w« 

 "•.'.' "yUM**! .'.' V.. V.X'.'.X-' 

 •t'.'.y.;'' r—^J'y', '.Vi'mh'.w*- 



f— v,v.\v.7.'. - ,-*w«v.,','.\>*"^0O00 z - 

 Ww.'.'/,'.> " 'W^WWiWft',' ','/ 



JANUARY 15-16 1950 



SEVEN FALLS 

 QUEBEC 



Figure 2. Storm microseisms from an east coast source recorded at representative North 



American stations. 



