Weather Blog: Groundhog Day earthquake rocks Northwest Arkansas and the River Valley Friday Night.

FAYETTEVILLE, Ark. (KNWA/KFTA) – Did you feel a whole lot of shaking going on last night just before midnight? No, it wasn’t your imagination, it was an earthquake MANY people and animals felt all across the Southern Plains, Mid-South and even beyond.

At 11:24 PM and 28 seconds CST, a moderate 5.1 magnitude earthquake with an epicenter 8 kilometers NW of Prague, Oklahoma and a depth of 3 kilometers sent a shockwave all across the southern United States.

Your Weather Authority Team was actually LIVE on social media giving an update about the rain coming in over the weekend late Friday night before the earthquake occurred. Check out our broadcast replay below starting at 14 minutes and 55 seconds into the update to see the reactions and how the information about the earthquake was unfolding in real time over the 2 hour long update.

https://www.facebook.com/danskoff/videos/1094796291936481

Tied for the 3rd largest earthquake ever recorded in Oklahoma, the seismic waves hit the Northwest Arkansas & River Valley area approximately 40 seconds later at 11:25 PM and 12 seconds CST. If you do some quick math, the energy released from the earthquake traveled 150 miles in 40 seconds at a speed of approximately 13,500 miles per hour or 3.75 miles per second. WOW that’s fast!

Many described hearing a low rumble sound followed by the shaking of their homes and furniture. Below is a video from Denton Sachs in SE Fayetteville where you can hear a whoosh sound followed by a door knocking sound, which was the arrival of the seismic energy.

Seismographs all over the region easily registered the earthquake as seen below.

Did you notice your pets acting scared or strange just moments before the shaking began? When energy is released from an earthquake, there is an initial wave of seismic energy called the P wave or the primary compression wave. P waves travel faster than S waves, and when they compress the land like a slinky, animals are very sensitive to these changes. This is why they often react to earthquakes before humans start to feel the S waves, which provide a rolling like motion.

Another example of animals being affected by the earthquake can be seen by the Twin Lakes radar near Oklahoma City. If you look closely shortly after 11:25 PM CST, a bunch of blue returns instantly show up just east of Oklahoma City and then slowly disappear over the next few radar scans. These are likely birds that took flight after the ground started shaking. The dual-polarization radar product called Correlation Coefficient (CC) shows these lower blue colored values, so the radar was picking up objects of different sizes and shapes over the small area. Pretty cool stuff!

Wondering about aftershocks? There have been a number of aftershocks, BUT they’ve all been very minor with the strongest registering a 3.5 magnitude. Click this link to view ALL the earthquakes (any magnitude) that have been reported just NW of Prague, Oklahoma.

Finally, what was the cause of this earthquake? Oklahoma semiologists continue to review the data and you can see the latest by searching #OKquake on Twitter (X), but the injection of wastewater with hydraulic fracking has been known to cause human-induced seismicity. Here’s a full statement released by the Oklahoma Geological Survey (OGS) earlier today.

There’s also been a statement from the Oklahoma Corporation Commission to order oil and gas wastewater disposal wells that are injecting into the Arbuckle Formation to start shutting down operations within 10 miles of the quake’s epicenter near Prague, OK.

As it turns out, there’s also a fault line in Lincoln county, Oklahoma called the Wilzetta fault. This is the same fault that was responsible for a stretch of earthquakes in 2011.

We’ll let you know if anything else rocks our world, so keep it here with Your Weather (and Geoscience) Authority Team for the latest information.

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