Joe’s Geology Blog: Yes KC…it was an earthquake

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Didn’t think I’d be putting on my geology hat today…but when a significant (for KC area) earthquake rolls through the region a lot of you have questions and I’m here to try and answer some along with bringing you some information that may teach you a thing or two about what happened this morning. As a result, we’ll forgo the weather aspect of air movement today and deal with the earth moving instead.

So was it really an earthquake? You betcha!  A 5.6 magnitude earthquake hit at 7:02 this morning centered in Pawnee, OK about 200 miles SW of KC.

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Why did we feel it here? Well this has multiple answers. One is that this was tied for the strongest earthquake that has hit the state of OK. There was another earthquake of similar strength back in 2011 in November. Since it was strong…it’s effects were felt further away than usual.

As a matter of fact…it was felt from MN down through TX and from the TX Panhandle towards IL.

Yes but OK seems to have a lot of earthquakes…why did this one get to us? One reason is that the earthquake was a “shallow” quake. Some of the bigger earthquakes that have occurred in the past happen deep within the earth…this one was closer to the surface…about 4 miles deep. As a result the “feel” factor of this was more spread out that usual.

Will there be more quakes as a result? Likely and it’s actually happened already. It’s hoped that this was the main event. IN looking at the archives…there was a 3.5 magnitude quake yesterday that we’re hoping was the “foreshock” before the main quake this morning. There have been about 6-7 aftershocks felt more locally in OK. What we don’t want to have happen is that this 5.6 quake be the foreshock to something more significant.

Was there damage? Yes in OK and to a very minor extent elsewhere it appears.

Is there a difference in earthquakes in the Plains vs California? Yes and no. No because when the earth moves the earth moves. Yes because of the way the earth moves. Out in CA there are numerous large faults or cracks in the earth’s crust. These cracks rub against each other or even duck under each other. This causes pressure to build up…until there has to be a release…earthquake. The bedrock there is not as solid as the bedrock here. As a result a 5.6 earthquake will be felt in a more localized area there than a 5.6 earthquake closer to KC. It spreads out more and is felt across larger areas of the Plains because our bedrock is so dense.

What was the cause of the OK Earthquake? This is where it gets a little controversial. Seismologists widely believe that mankind is causing the rash of earthquakes in OK that have been an issue over the past 10 years or so. It’s true that there are faults in OK…and in fact they extend up through the Plains

 

However what’s happening in OK is crazy. According to wikipedia “Beginning in 2009, the frequency of earthquakes in the U.S. State of Oklahoma rapidly increased from an average of less than two 3.0+ Mw earthquakes per year to hundreds in 2014 and 2015. Thousands of earthquakes have occurred in Oklahoma and surrounding areas in southern Kansas and North Texas since 2009.[7]Scientific studies attribute the rise in earthquakes to the disposal of salt water produced during oil extraction that has been injected more deeply into the ground.[8][9]

“According to data from the United States Geological Survey, there have been approximately 2,186 earthquakes in Oklahoma with moment magnitudes greater than or equal to 3.0,[12] about 71 earthquakes with magnitudes greater than or equal to 4.0, and two earthquakes with magnitudes greater than 5.0 associated with the earthquake swarms from the beginning of 2009 through August 14, 2016.[13]

There is a lot of information on their page here.

What is the difference between 3.0…4.0…5.0….6.0 earthquakes?

Well the best way of talking about this is by the energy released by these earthquakes. The difference in energy released between a 3 and a 4…

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a 3 and a 5

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a 3 and a 6

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Even the subtle difference between a 5.0 and a 5.6 is significant

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The key to all this is the energy release of the earthquake itself.

Does MO have earthquakes? Yes we do as a matter of fact. The epicenters in MO of significant ones though is rare but there is one area that is always a concern and that is the New Madrid zone in the far SE part of the state.

Was this earthquake related to the hurricane back east? No

Is there anything I can do about this? Well not really. You can purchase earthquake insurance as part of your home insurance program. You can do some of the same things you do in terms of itemizing your home contents (like you should for severe weather season) but in reality there isn’t anything you can really do. You can learn some safety information though.

Do animals sense these events before humans? Likely yes. Dogs and cats can sense these events possibly because they are picking up on vibrations before humans do. Birds can also feel the vibrations before humans do and often will fly en masse split seconds before we feel the rocking.

How far did the earth shaking travel? Well across the world actually.

Now let’s go to the other side of the world…Estonia to be precise.

Where can I find more information about the events from this morning? Well the USGS has you covered! Go to this link!

All I can say is that if that was a far off feeling of a 5.6 earthquake…I don’t want to know what a bigger one feels like up close unless I’m out in the middle of nowhere where nothing can fall on top of me!

Joe

 

 

 

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3 comments

  • Patrick Trudel (@sedsinkc)

    Nice blog, Joe. Good to see geology get some exposure. That was an interesting event this morning. Being horizontal and 3/4 asleep when it happened, it reminded me of flying first class on an overnight flight a couple years ago when the plane encountered mild turbulence. Then my girlfriend ran upstairs where I was, shouting OMG we just had an earthquake!! On a more serious side, the same factors that allow us to feel a 5.6 quake in Oklahoma could mean big trouble for St. Louis and Memphis, and to a lesser degree, KC, should the New Madrid seismic zone ever go off with a near magnitude 8 event as what happened twice in 1811 and 1812.

  • Kevin James bailey

    Not bad for a weather man Joe! Glad you did point it to Fracking & yes, for years salt water disposal has been a concern of mine also, because of the magnitude in the past 10 years. If it was up to the O&G industry they would utilize open evaporation lagoons & market the salt for road safety, but regulatory requirements require by EPA & UIC for ALL deep well disposal of process, formation fluids’, salt water or to be treated to Drinking Water Standards and discharged into a stream or river! My first 3 years as a independent petroleum geologist involved several disposal well permitting.
    I was also involved in the new replacement Class1 UIC disposal well(2006) for Deffenbaugh Industries which is located in Shawnee, KS Johnson county landfill.