Refracktion. I am no geologist but common logic suggests that...

Refracktion. I am no geologist but common logic suggests that your point and the highlighted statement actually support in favour of Cuadrilla point of argument.

3D seismic couldn't detect the faults that caused the 2 biggest tremors of 2.3M and 2.9M. So yes everyone I think can agree on that.
But looking from the other side view and from Cuadrilla seismic models, these "undetectable" faults appear to cause the max magnitude of 2.9M. In Cuadrilla model they predicted these undetectable faults can only cause a maximum magnitude of 3.1M.In term of seismic anything under 3M has very limited damage other than a scary shaking that understandably are annoying disturbing. But in term damaging buildings, it is not considered as dangerous or unacceptable.
3D seismic map would have detected any big faults that can cause >4M.
I am no geology expert. Just my understanding of the facts.