Oklahoma Geological Survey annotated 24 hour low frequency seismograms for year 2004.

Four most recent days.

2004 DEC scroll

2004 NOV scroll

2004 OCT scroll

2004 SEP scroll

2004 AUG scroll   animated

2004 JUL scroll   animated

2004 JUN scroll   animated

2004 MAY scroll   animated

2004 APR scroll   animated

2004 MAR scroll   animated

2004 FEB scroll   animated

2004 JAN scroll   animated

Monthly seismogram statistics

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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SHORT EXPLANATION:

These seismograms were produced by a broadband seismometer in the Leonard
walk-in vault. They show only vertical (ie, not East-West or North-South)
ground motion. 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.

Some earthquakes are labeled (average 3.4 based on 2001 JAN through NOV)
to show the earthquake region, the distance from Leonard
in great circle degrees (eg. D=120), and magnitude (eg 5.1mb). Definite 
earthquake surface waves of earthquakes not located at the time the figure
was posted may be marked with a ?.

Some of the seismograms with large surface waves which may obscure other smaller
earthquakes are SIGNED ROOT COMPRESSED  This
consists of taking the root (from the 1.1 root to the 3.0 root) of each
number while keeping the original sign (plus or minus) of the number.

LONG EXPLANATION: hardware and software details. The epicenters used in annotation are from these three sources: 1. SED = Swiss Seismological Service/Schweizerischer Erdbebendienst seismo.ethz.ch/redpuma/redpuma_ami_list.html 2. USGS = U.S. Geological Survey, National Earthquake Information Center. neic.usgs.gov/neis/bulletin/ 3. KNET = Kyrgyzstan Real-time Broadband Array epicenter.ucsd.edu/~quake_KN/bulletin.txt SED epicenters include USGS and KNET epicenters, as well as epicenters from several other sources. These web pages are processed by a NAWK program which calculates the distance to Leonard, Oklahoma U.S., and the expected arrival times of P/Pdif/PKP and LR. Source 1. tends to have lower magnitudes than source 2. If the type of magnitude was not labelled by the source, it is listed as simply "M" (eg 5.1M).

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