Wow, and I thought they would get to 5's at least. The earthquake mechanism has advanced to the point where 4's are an every-day occurrence. I didn't think they would take action on those. That would explain why earthquakes have moved further north. They might not be shutting down a lot of wells, but nobody is going to inject frack waste where there has been an M4. These companies know perfectly well what is happening.
At this rate, the whole OK mechanism may shut down for waste injection. I understand they have other places, but probably nothing near the volume for injecting straight into the basement. They use the fiction that they are injecting into the fractured limestone right above the megathrust, but we know from the Bruce Black Hole what that means. :)
Even this company claims they are only injecting rock water, but we know earthquakes are only activated with surface water. I wish everybody would come 'clean' on this issue, but there is no hope there.
Anyway, frack waste injection will soon be chased out of there, and I wonder where it will go.