Oklahoma Geological Survey annotated 24 hour seismograms for the four most recent days.
The LOW FREQUENCY seismograms show mainly surface waves from distant
earthquakes. The MEDIUM FREQUENCY seismograms show larger 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.
Only the "larger" Oklahoma earthquakes are seen on
these grams because most of their energy is higher frequency than the
medium frequency band.
Starting in late MAY 2006 the LOW and MEDIUM frequiencies are combined
into one seismogram. The high frequency seismogram will usually not be
posted unless it includes one or more Oklahoma earthquakes.
Tragic blasts reported in the news (bombs from aircraft, truck bombs, etc) SELDOM show on these seismograms, because they put most of their energy into the air, and little energy into the earth.
These seismograms were made with freeware/openware including Seismic Analysis Code, ImageMagick, various PERL scripts, vi editor, VSFTPD, and SuSE Linux operating system.
The most recent seismogram appears at the top. The page can be scrolled downward through the previous three days.
Seismograms for this month (to date) and earlier months.