- Earthquakes – what makes them trigger?
- How big are the disturbances introduced by “fracking”?
- Blackpool will have fewer, not more, discernable earthquakes if fracking goes into production
By Bill Butterworth
3 December 2014
The news this week of Ineos announcing a very significant investment in UK shale gas exploration will, yet again, open discussion on shale gas. Is there such a thing as safe shale and what does common sense tell us about where we are now? You don’t have to be a qualified seismologist to understand something about fracking and earthquakes.
Consider a few billion tonnes of rock a mile or two below the surface and put some water under pressure into a crack in that rock. Mostly it is not necessary but suppose also that you stick in a small explosive charge. What does common sense tell you is going to happen?
For those old enough to remember the cold war between the West and The Soviet Union, each testing bigger and bigger hydrogen bombs usually below the ground, they may remember that there was a fear that we might crack the surface of the earth’s crust. These weapons were hundreds, even thousands of times larger than the bombs dropped on Japan during the Second World War.
Now go back to fracking. The process uses water under pressure. Sometimes it uses small charges of explosives – we are talking kilos, not even tonnes of explosives against millions, or even billions, of tonnes of rock. Blackpool has always had earthquakes. Millions, even trillions, of tonnes of earth’s crust is under tension and stress and, occasionally, it moves a bit. Now, if that tension and stress was on the edge of moving and causing a detectable quake, what fracking might do is trigger the quake which would have happened anyway. More than that, what the injection of fluids are more likely to do is lubricate the movement which was about to happen anyway and make a series of short movements which would reduce the effect of the quake. Blackpool might well have less detectable earthquakes, not more.
There is an expression used sometimes by journalists: “If the truth is stretched far enough, it becomes a lie.”
Think about it. Who is stretching the truth too far?