Oklahoma Geological Survey annotated 24 hour low frequency seismograms for year 2001. The seismograms show 24 horizontal lines, one for each hour of ground motion. The data is filtered so that it shows mainly surface waves from distant earthquakes. Geological Survey, National Earthquake Information Center. Sources 1. and 3. tend to have lower magnitudes than source 2.
Dates below are in the form of yyyymmdd.
The dates are in inverse order. The most recent seismogram is listed at the top.