March 2011 Tôhoku M9.0 (AKA Honshu) earthquake pinned the scale on the Force Balance Vertical seismometer. The earth rang like a bell for a couple days. The figure is a plot of a Fast Fourier Transform from 60 minutes of Inyo seismometer recorded data. Data was recorded about 12 hours after Tohoku earthquakethe 9.0 earthquake. Time period did not include any observable aftershocks. Notice the defined peaks. Click plot to expand size.

 

 

 

 

 

 

 

Mid Atlantic Ridge Quake