5 November 2011

Oklahoma Rocks! After The Summer Bake, Sooners Get A Shake!

Posted by Dan Satterfield

Seismograms from nearby instruments. The top trace was just a few kilometers from the epicenter!

Remember “shake and bake” chicken? Well Mother Nature seems to have it backwards, because after a summer of being baked, Oklahomans just got the shake! A magnitude 4.8 quake hit near Sparks, Oklahoma at 2:12 am (07:12 GMT) Saturday morning, and even caused some damage in the nearby town of Prague. The quake was very shallow at 3.5 km depth and was felt over a large part of the state.

My daughter lives in our house in Oklahoma City, and not only did it wake her up, she said the 102 year old house felt like it was riding a wave! I have nephews in Tulsa and they also felt it strongly. Quakes of this magnitude are rare in Oklahoma, but I can remember a couple of minor shakes growing up in Tulsa. Nothing like this though, and I’m jealous (that’s an understatement!) of my daughter for experiencing it!

While a meteorology student at the Univ. of Oklahoma, I took a summer job at the Oklahoma Geological Survey south of Tulsa. It was a fascinating experience and I’ve been interested in geology ever since! The Oklahoma Geological Survey reports the quake was very near the location of a 4.3 mag. quake in February of 2010 and it was probably on the Wilzetta fault. At least three aftershocks have been felt through Saturday afternoon.

UPDATE: 11PM CDT 5 November 2011.

I was talking with my daughter using Apple Face-Time at 10:50 PM tonight and we were discussing the early morning quake, when she suddenly said “OMG, it’s happening again!” I could hear the house creak and saw the hanging lamps sway. Thank you Steve Jobs for letting me share the quake with my daughter 700 miles away!

This quake was bigger than the one this morning- the preliminary USGS magnitude is 5.2! Same epicenter near Sparks,OK. I think this means the quake this morning was a foreshock (pre-shock). Will email my geological friends to make sure.

Update 11:35 PM US CDT:
USGS- just upgraded to 5.6! This may be the strongest ever recorded in Oklahoma.

Update: Sunday- It is now officially Oklahoma’s strongest quake.