On 8/14/2012 11:18 AM, Dave Nelson wrote:
> If you look at  my force balance instrument traces on the PSN current 
> seismicity web site you will see long period signals in the few hours 
> after the event. Theses are the whole earth or earth normal modes 
> which were excited by the event.
> The instrument long period corner is 50 seconds and the motion is at 
> significantly longer periods but the motion is so  large the 
> instrument response is sufficient to provide a nice display.  My 
> Trillium Compact with its 120 second corner is much better but it is 
> not an amateur class instrument.
> I have made a spectrum in Winquake and the individual modes are quite 
> apparent and individually identifiable.
> Interesting stuff !!
Without going back and looking, I believe this is the largest deep quake 
in the last ten years....anyone know better?

  
    
  
  
    
On 8/14/2012 11:18 AM, Dave Nelson
      wrote:

    
    

      
      
      
If you look at  my force balance 
          instrument traces on the PSN current seismicity web site you
          will see long period signals in the few hours after the event.
          Theses are the whole earth or earth normal modes which were
          excited by the event.
      
 
      
The instrument long period corner
          is 50 seconds and the motion is at significantly longer
          periods but the motion is so  large the instrument response is
          sufficient to provide a nice display.  My Trillium Compact
          with its 120 second corner is much better but it is not an
          amateur class instrument. 
      
 
      
I have made a spectrum in
          Winquake and the individual modes are quite apparent and
          individually identifiable.
      
 
      
Interesting stuff !!   
    
    Without going back and looking, I believe this is the largest deep
    quake in the last ten years....anyone know better?