December 18, 2016
By Corey Jones
...Specifically, (click here) whether there’s a definitive human fingerprint on the unprecedented Prague earthquake sequence in 2011 remains murky, according to some of the latest research available. The magnitude-5.7 main quake was sandwiched by a 4.8 foreshock and 4.8 aftershock.
A study published Nov. 30 by two Stanford University geophysicists developed a model to show how man-made quakes are expected to respond to the substantial cutbacks in 2016 of wastewater injection. The peer-reviewed article reported that the three largest Prague quakes occurred “unexpectedly early” in the induced seismicity sequence, the beginnings of which the authors pegged as 2009.
“Because the Prague sequence does not fit our overall model, it does not allow us to conclude whether it was triggered by injection or not, as our model characterizes the general relationship between an injected volume and seismicity in a crustal volume as a whole,” according to the study. “A localized pressure increase in a limited area could always trigger seismicity on a given fault.”
The scientists say it’s unclear if Prague was a definitive product of human actions because that particularly strong sequence happened on the front end of the state’s rise of induced seismicity, not conforming to their general model of the situation....
Corey Jones took a scientific article and applied his own meaning to it. This is called living a lie for economic goals. I would not expect this either. It is well established by scientists in Oklahoma these quakes are directly related to hydraulic fracturing.
The water, with corrosive chemicals, introduced into the drilled wells was like adding grease to gears. The gears seize up and become immobile without grease or oil to allow them to move freely. That is exactly what corrosive chemicals mixed in water did for the land. It allowed methane out of cracks all right, but, it did so with methods that permanently damaged the land under the wells. The water was the hydraulic part that moved into cracks in the rock and provided pressure to move the rock and increase the seismic activity.
The article looks at the decreased volume of water injected into the wells to determine if that is enough to end the quakes. The article has nothing to do with whether or not the practice of hydraulic fracturing caused the quakes. Of course, the hydraulic fracturing caused the quakes. Oklahoma was a state that rarely had quakes and not they happen at least weekly if not once a day with aftershocks.
"How will induced seismicity in Oklahoma respond to decreased injection rates"
By Cornelius Langerbruch and Mark D. Zoback
Scientific Advances, 30 November 2016, Vol. 2, No. 11
In response to the marked number (click here) of injection-induced earthquakes in north-central Oklahoma, regulators recently called for a 40% reduction in the volume of saltwater being injected in the seismically active areas. We present a calibrated statistical model that predicts that widely felt M ≥ 3 earthquakes in the affected areas, as well as the probability of potentially damaging larger events, should significantly decrease by the end of 2016 and approach historic levels within a few years. Aftershock sequences associated with relatively large magnitude earthquakes that occurred in the Fairview, Cherokee, and Pawnee areas in north-central Oklahoma in late 2015 and 2016 will delay the rate of seismicity decrease in those areas....
That statement in the articles abstract states there will be continued seismicity in this area of the country BECAUSE OF LARGE MAGNITUDE QUAKES in the recent time of 2015-2016. This article is not about whether or not the quakes are caused by hydraulic fracturing or not, it validates there is increased seismic activity and due to that increased seismic activity, even with less water in the wells the quakes will continue to happen.
The graph below is from the article. It clearly shows the increased quake activity with hydraulic fracturing. Prague M = 5.6 was the first warning shot. The quakes increased after that. Prague M=5.6 was the quake that was the grandfather to all the quakes to follow.
Normalized pressure does not mean the pressures within the rocks are normal, it simply means the pressure causing the quake was not found at that depth of 3 kilometers below the well.
Prague M = 5.6 was the beginning of more and deeper cracks in the rock that would lead to increased instability in the land. The more water introduced with corrosive chemicals the more quake activity was going to occur. With less water in the wells today, there is also less corrosive chemicals and less hydraulic pressure. The future of quakes in Oklahoma depends on whether or not the land has finally settled into a stable balance. That means Oklahoma stops it's hydraulic fracturing. If that continues there will be continued instability in places where cracks were induced by human activity.
