Welcome to the Earthquake Capital of the US

[touchring]

Re: Welcome to the Earthquake Capital of the US

Interesting that earthquakes are increasing when oil and gas activity has been declining for more than a year now. Some sort of hysteresis effect in the rock mechanics perhaps? Or a change in the quality and sensitivity of the equipment doing the measuring? Or some other factors we don't know?

Don't know about quakes, but possible that the rocks underneath the ground are now unstable and there has to be a big one to shake everything back into place? Think the 2004 Indian ocean and the 2011 tohoku megathrusts, they are all preceded by smaller quakes.

[santafe2]

Re: Welcome to the Earthquake Capital of the US

Don't know about quakes, but possible that the rocks underneath the ground are now unstable and there has to be a big one to shake everything back into place? Think the 2004 Indian ocean and the 2011 tohoku megathrusts, they are all preceded by smaller quakes.

This was the warning USGS made for Oklahoma in 2014 when quake counts started moving up exponentially. They've had more than 6,000 in the last year. Only a handful have been over 5.0 but it doesn't appear anyone understands what they're playing with geologically. Like that other thing we don't talk about here any longer, it might be a good idea to be cautious until Oklahomans understand what they're dealing with.

[lektrode]

Re: Welcome to the Earthquake Capital of the US

....but it doesn't appear anyone understands what they're playing with geologically. Like that other thing we don't talk about here any longer, it might be a good idea to be cautious until Oklahomans understand what they're dealing with.

like what 'other thing' - coal ?

[lakedaemonian]

Re: Welcome to the Earthquake Capital of the US

New Zealand has a fairly unique distinction in that it is an island country where the Ring of Fire passes directly under the South Island. Earthquakes over magnitude 5 are quite common and as you know from the 2011 Christchurch quake, they can be deadly. Most of the earthquakes in Oklahoma are about half that magnitude but as you know, 3.0 aftershocks get on your nerves after a while and if there hasn't been a big quake, you're really wondering if it's a foreshock.

To give you some idea of the magnitude of change in earthquake activity in Oklahoma, let's take a closer look at earthquakes of 2.5 magnitude or higher in Fairview, the little town of 2,600 people that just experienced the 5.1 on Saturday.

There were 11 earthquakes from 1987 through 2013 or 1 every ~2.5 years.
There were 13 earthquakes in 2014
There were 85 earthquakes in 2015
There were 92 earthquakes in the first 58 days of 2016
There were 13 earthquakes on January 7th alone

They've gone from one earthquake every 900 days to one every 15 hours. That, is one hell of a correlation!

I think we've dealt with the same, despite the ominous Ring of Fire.

Anecdotally, we felt 1 local light quake in early 2001, and 1 very, very distant quake approx 2009.

With what USED to be a very English old school architecture city(often called "the most English city outside of England") going back over 150 years, I think our longer term(in human terms) local activity was also quite light.

EDIT: to add....by English Architecture reference I meant stone/masonry load bearing buildings that do not do well in earthquakes, and have since been involuntarily removed.