46 



Symposium on Microseisms 



seisms is shown. The Columbia vertical shows 

 only weak activity at the time of the latter 

 event. The quake at 1740 is shown well on 

 all traces. 



Case 3. May 16-17, 1952- On Figure 6 the 

 2-second trace shows an amplitude increase 



about 1800, May 16, with the other traces show- 

 ing gentle increases following the quake at 

 2100. The 4.5- and 6.4- second traces show 

 very prominent activity during the first 12 

 hours of May 17, while the 2-second trace has 

 returned nearly to background level. Weather 

 chart A, (1830, May 16) Figure 6 indicates a 



5/IM3 



Figure 8A. Wave-gauge records of May 11-13, 1946 made near Woods Hole, Massachusetts. 



