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5.1 magnitude earthquake in Oklahoma felt in Arkansas


Seismic activity on the rise in Central U.S over past 12 months

By Ralph Hardin

Prague, Oklahoma is approximately 400 miles from Crittenden County, but any large-scale seismic activity in such relatively close proximity to the volitile New Madriz Seismic Zone (which includes parts od Arkansas, Missouri, Tennessee, Kentucky and Illinois) is worth taking note of, especially when it’s felt by Arkansas residents.

Such was the case when the aftershocks of a 5.1-magnitude earthquake near the eastern Oklahoma of about 2,000 residents rolled through the underground of the Fayetteville area just after 11:24 p.m. Friday night.

The earthquake originated 6 kilometers outside of Prague, according to the United States Geological Survey (USGS).

Fayetteville is less than 200 miles away from Prague and currently falls within the 'light' level (level IV) on the USGS ShakeMap.

USGS reports indicated that the earthquake on Feb. 2 could be the mainshock of a series of five events. The initial recorded activity was a 1.5 on the Richter scale at the same epicenter on Jan. 19.

The Central U.S. has seen an uptick in seismic activity over the past year-and-a-half.

Initial estimates rank Friday’s event to be among the top three greatest to affect Oklahoma since 1900, according to historical data and the strongest in more than 40 years.

Earthquakes registering between 5 and 5.9 on the Richter scale have the potential to inflict minor damage to buildings and other structures. No reports of damage or injury have been made at this time.

The USGS report placed the event at approximately 3 kilometers in depth, nearly 7 kilometers below the average depth of seismic events across the globe.

“The shallow depth of the quake caused it to be felt more strongly near the epicenter than a deeper quake of similar magnitude would,” a Volcano Discovery report said.

Residents of Northwest Arkansas as well as parts of Kansas and Missouri have reported experiencing a brief rumble or tremor since the time of the earthquake. The USGS reporting system received over 15,000 submissions within the span of an hour.

The current USGS Aftershock Forecast predicts that there is a 57% chance of another potential aftershock within the next week.

While not officially part of the New Madrid Seismic Zone, the faultline that runs through Oklahoma does share some common tectonic plate area with the infamous seismic region. The Boston Mountains are a part of the natural topographic surface features between the two seismic zones. Most of the other significant seismic zones in the Unted States sit west of the Rocky Mountains or in Alaska and the Hawaiian Islands, with the exception of the Virginia Seismic Zone along the East Coast.

Recent seismic activity in the Central U.S. has not been limited to the slate of Oklahoma.

See QUAKES, page A3

Photo courtesy of USGS QUAKE

From page A1

A very small earthquake occurred on Sun Feb 4, at about 9:30 p.m., 4.32 kilometers northwest of Tiptonville, Tennessee. The magnitude was 1.4, which is considered a minor quake by USGS.

USGS officials advise those in the vicinity of any earthquake to report whether they felt any shaking at earthquake.

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