But Oklahoma keeps going.
That's the trouble with this whole injection thing - we are missing the vital information of pressure-volume charts. Since these are all cowboy operations with gov't influence, they can get away with this. And thus you can never really prove what is happening. The new Arkansas swarm was proving to be a growing Baby New Madrid, right near a town. Did they stop it? Who knows?
When you are injecting into the Precambrian, there should be three types of responses.
Tight rock - This is the rock between the megathrusts. Do not collect any money, do not pass Go. This is a dry hole.
Randomly fractured rock - This should be rare, perhaps in the hanging wall of a megathrust. Appears to be the case with the wells near the lake in Ark. Earthquakes tightly clustered around the wells. The pressure should remain steady, with a slow upward creep due to clogging.
Earthquake Sustaining Mechanism - Happened with the first Ark injection. Bigger and bigger earthquakes forming a thrust and shear sustaining mechanism. A growing New Madrid! Pressure should drop, and they would naturally increase volume. A great money-maker until the earthquakes get too big and they stop. In Ok they never stop!