ARPSN - Amateur
  Radio Public Seismic Network
  Cobb, CA - Macon, GA - Redwood City, CA - Comparison
  FFT-CSP Animation - April 2009
North/South - East/West - Cobb [Mountain], CA (PSN)
  
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North/South - Redwood City, CA (PSN)
  
North/South - East/West -  Macon, GA (Pier)
  
  
  -
  
[Notes: Graph Amplitude (DB) varies on all three (3) site locations. Macon Pier Channel 1 is set East/West and Cobb [Mountain] Channel One is set North/South. Period (sec) varies on Macon, GA Pier plots. Large Animation: - 2009 March (Cobb [Mountain], CA) - 2009 March (Macon, GA - PIER) - 2009 March (Redwood City, CA -PSN)]

  For More Information:
  A New Look at an Old Tool:
  the Cumulative Spectral Power of Fast-Fourier Transform Analysis
  Sheng-Chiang Lee and Randall D. Peters
  Physics Department, Mercer University, Macon, GA 31207
  http://www.flyingsnail.com/AmateurRadio/VolksMeter-FFT-CSP.html
 Presented by ARPSN
  Amateur Radio Public Seismic Network