Oklahoma Geological Survey annotated 24 hour seismograms for 2007 APR

The LOW FREQUENCY seismograms show mainly surface waves from distant earthquakes. The MEDIUM FREQUENCY seismograms show Oklahoma and (some) other North American earthquakes. They also show P and PKP phases from moderate to large distant earthquakes. Finally, they show quarry blasts. These limestone surface mining blasts are mostly in NE Oklahoma, but a few may be in other parts of Oklahoma, or Missouri, or Arkansas, or Kansas. A few of the smaller blasts are from Oklahoma or Kansas coal strip mines. Oklahoma earthquakes are shown on the HIGH FREQUENCY grams, as well as some quarry blasts.

Starting in late MAY 2006 the LOW and MEDIUM frequiencies are combined into one seismogram. The high frequency seismogram will usually not be shown unless it includes one or more Oklahoma earthquakes.

The most recent seismogram appears at the top. The page can be scrolled downward through the rest of the month.

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Seismogram Index For Year 2006

Seismogram Index For Year 2005

Seismogram Index For Year 2004

Seismogram Index For Year 2003

Seismogram Index For Year 2002

Seismogram Index For Year 2001

Seismogram Index For Year 2000

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