Oklahoma Earthquake?

[seekermeister]

I was quite surprised that ~20 minutes ago, that my apartment started shaking for a few moments. While some Californians would find this too common to comment, it is very rare here. I have NEVER felt an earthquake here before, even though Googling, I found that there are a few minor earthquakes around the state.

I tried to find a website that I came across once, that had a live display of current seismic activity around the world, just to see if I could confirm it, and get a measurement of it's strength, but had no luck.

I also found articles that spoke of earthquake in the UK that was caused by fracking by an oil company, instead of the usual fault line movements, which seem more likely here also.

Does anyone know of the website that I spoke of, that charts live seismic activity?

 

[seekermeister]

It wasn't what I was thinking of, but I did find info on it at the USGS website. It was two shocks a few seconds apart, the first was 4.7 and the second 3.4, 6 miles North of Prague, Oklahoma, which is not too close to here.

EDIT: The distance to Prague is 68 miles South, so that would put the epicenter of the quake at about 62 miles South of here. At first, I thought that one of my neighbors must have blown something up in the complex.

 

[Airbot]

I use USGS site for the live updates, as you mentioned.

Latest Earthquakes in the USA - Last 7 days

Maybe the big earthquakes that you would feel are rare there, but not sure how rare any earthquakes there are. That area around OK city usually has 3.0 and lower average earthquakes quite regularly that I've seen monitoring the site daily for over a year now. You're just not feeling them.

There's obviously some small isolated minor fault line/s there near OK city that isn't recognized/officially established yet.

 

[seekermeister]

I will admit that I have never paid too much attention to earthquakes living here, because I have never felt one before, nor have I ever heard of one mentioned on the news. Looking at one earthquake map, it seems that like you say, that there are probably some very minor tremors nearby, but so mild that nobody notices them.

 

[seekermeister]

That's ominous...about 5 minutes ago, there was another quake. I hope these are not leading up to a truly big one. I checked the USGS website, but they had not yet updated their info.

 

[Brink]

It must have been a decent one. I felt a slight trimble for a couple of seconds where I'm at in TX.

 

[Airbot]

Yep. 5.2

Magnitude 5.2 - OKLAHOMA

 

[Golden]

That's ominous...about 5 minutes ago, there was another quake. I hope these are not leading up to a truly big one. I checked the USGS website, but they had not yet updated their info.

Its very common to experience what are termed after-shocks, post an earthquake proper. The crust is rigid, so the rocks destress in response to movement along fault planes - this is what you are experiencing.

In a major earthquake there are no small precursor quakes : energy builds up on major fault lines and then is suddenly released : this is the typical earthquake.

 

[seekermeister]

This one was ~ 75 miles Southwest of here, but still in the general area of the last shake. A little stronger at 5.2 and it lasted somewhat longer than before.

 

[seekermeister]

That's ominous...about 5 minutes ago, there was another quake. I hope these are not leading up to a truly big one. I checked the USGS website, but they had not yet updated their info.

Its very common to experience what are termed after-shocks, post an earthquake proper. The crust is rigid, so the rocks destress in response to movement along fault planes - this is what you are experiencing.

I would tend not to consider this an after shock, simply because the magnitude is increasing, rather than abating.

In a major earthquake there are no small precursor quakes : energy builds up on major fault lines and then is suddenly released : this is the typical earthquake.

I'm certainly no seismologist, but it is my understanding the there are precursor shocks prior to the primary one at times.

 

[Golden]

In relatively small earthquakes that is correct, in fact what is happening is a series of invidual small quakes. In major earthquakes the energy is released very suddenly when the fault planes can no longer contain the stress built up in the rocks on either side of them. The sudden release of energy is what makes earthquakes so damaging.

 

[seekermeister]

Maybe I have been watching too much TV, but I thought that was the point of having seismic stations monitoring known areas...to provide a warning of a major quake by reading the lesser ones that might lead up to the big one.

 

[Golden]

Thats the theory......but the link between smaller quakes and large ones is not yet proven, especially in areas prone to earthquake actvity (e.g. Japan, New Zealand, west coast of the US which all lie on or close too the Pacific plate boundary). If we could predict them, we could have avoided the devastation and loss of life as occurred in the recent earthquake off the coast of Japan.

 

[Airbot]

Larger earthquakes can have "foreshocks" leading up to the larger event. Depends on the type of fault line, and it's movement. They're not all just of one type. It's not a certainty of "no, they never will have them".

Foreshock

 

[Brink]

Yep. 5.2

Magnitude 5.2 - OKLAHOMA

Just been upgraded to a 5.6 :shock:

Epicenter: Sparks, OK

 

[seekermeister]

I don't imagine that my distance makes me safe, but I'm glad that I don't live in Sparks. I wonder what kind of damage that they might have had?

 

[seekermeister]

On the Richter Scale, it might be a minor quake, but it is the strongest one ever reported in Oklahoma:

5.6 magnitude earthquake shakes Oklahoma | NewsOK.com

 

[Golden]

Larger earthquakes can have "foreshocks" leading up to the larger event. Depends on the type of fault line, and it's movement. They're not all just of one type. It's not a certainty of "no, they never will have them".
Foreshock

Unfortunately, foreshocks aren't reliable methods of predicting a major quake event, hence they are largely disregarded, especially in areas where quakes pose hazards, such as areas on the Pacific plate boundary where foreshocks can be a daily occurence. It would not be practical for evacuations to happen every time a minor quake is classified as a foreshock - in some places this could be weekly, possibly even daily.

 

[Airbot]

Personally never mentioned foreshocks being a valid method of prediction. Merely was a counter to "In a major earthquake there are no small precursor quakes", which isn't entirely an absolute.

 

[Golden]

I'm not wishing to start an argument, just adding more to the discussion Airbot. I'm a geologist by profession so just trying to add some of my insight into a topic that is of interest to me.

Regards,
Golden