[okie01]

Fracking has been employed to re-vitalize old wells since the late forties. Send a charge down the hole, explosion creates cavity and fractures rock, otherwise unrecoverable oil is pumped out of the cavity.

The difference is that those were vertical wells. Fracking today is employed in horizontal drilling. It is the combination of these two technologies that led to the "fracking boom".

Given that racking has been around so long without having any notable seismic influence certainly suggests it's not the culprit.

A more likely culprit is disposal wells -- which pump the spent saltwater back into the ground under high pressure.

[Vision]

You may be right but it doesn't seem like a good idea to me.