Oklahoma City Growing an M7 Earthquake
I'm expanding on an afterthought. As we are aware, all recent OK earthquakes are a result of a massive effort of injecting all the watery waste that Ohio has rejected. No matter what, the huge US fracking industry must get rid of all that shale water. As other states close up, the price for injection goes up, sort of like the useless 'war on drugs'. :)
The ideal way to make lots of money in the injection biz is to punch through to the Precambrian, and find one of the 'magic holes' where you just have to pour the stuff down by the truckload. These things only exist in the hanging wall of the megathrust.
Toronto has this pattern, with the potential M7 under Hamilton.
Now Oklahoma is developing the same pattern, not due to a Great Lake, but rather, massive injection.
Don't forget that Toronto has been recording since 1991, and who knows what they have in OK! But I really think the pattern will fill in.
I don't really want to qualify with the odds, etc. I don't think anybody will read this. But the most interesting scientific point is whether activity in the outer disturbed zone actually contributes to the sustaining mechanism of the main fault. For Toronto, I used to think that this outer zone was a passive result (disturbance) of activity on the main fault. This is something like mining.
With OK, I am coming around to the opinion that it is a double feedback. Every earthquake in the zone converts NE main stress to a NW strain, which pushes on the main fault. The actual sustaining mechanism is thus the entire thing! This is an entirely different mechanism than New Madrid and little growing Arkansas. All brought on by injection -- It's fantastic!
In a way, this pattern of NE fault and NW disturbed zone functions the same way as the conjugate set of the New Madrids. The faults grow bigger and the disturbed zone also grows. This has taken a great weight off my shoulder, since I couldn't see how a Toronto mechanism could grow. The concept of stress feedback makes me happy. :)