Second thoughts. Seismicity is not exactly an area that I can claim any great expertise. I have discussed subsurface waste disposal with a colleague tasked with evaluating its potential in a Canadian province, worked with industry geophysicists (you get to learn their language) and have discussed earthquakes with an expert within UEA. However, upon some questions here I've been giving the best of my understanding, but this could be I've been winging it. Such was the case with evaluating the energy required to shake a pile of rock compared with causing ground vibrations from a wind turbine. What I had forgotten was that most of the energy in a seismic wave is conserved as the wave is transmitted from one place to another. Thus the entire volume of rock is not being shaken at the same time. This realization came to me when I considered artificial seismic waves and the energy needed to send these waves through a rock sequence either by using explosives or a "ground- thumper". Large, but not that large.
Nevertheless, although I don't actually know how much energy might be transmitted into the ground from a wind turbine, I doubt it is anyway comparable with that needed to induce a usable seismic wave. If it did, the concrete bases wouldn't last long before being shaken to bits (I guess - winging it again).

SG. I think you may be confusing magnitude with intensity. But I have already explained why wind-induced tremors shouldn't be called earthquakes. And if you think the energy that might be imparted into the ground by the wind is in anyway comparable with the energy needed to shake a pile of rock several thousand metres thick over many square kilometres, then I despair.

GolfCharlie
"aren't these "earthquakes" exactly what was Intended by the hydraulic fracturing process?"

You have it in one. I'm sure the Industry would have hoped that the induced seismicity would have been even lower, so that the risk of inducing more damaging effects would be virtually non-existent. But that is not the case in Lancashire, no matter how much you would wish to support the fracking industry. The seismic risks are not zero. The same applies to the subsurface waste disposal industry which has been associated with damaging earthquakes. I imagine the regulations relating to avoiding seismic damage associated with subsurface waste disposal have been modified to apply to fracking in suspect areas like Lancashire.

SG
"If we put the same monitors at the base of giant wind turbines, what would they read ?
Would it be called "earthquakes" ?
No, it wouldn't. It might be called micro-tremors or vibrations, but they wouldn't have the same energy nor, more importantly, would they have the same cause - a readjustment of rock in the subsurface accompanied by over-pressures.

Supertroll, aren't these "earthquakes" exactly what was Intended by the hydraulic fracturing process? If they are being monitored, isn't this just the sort of evidence that the fracking industry has been denied the opportunity of obtaining, in order to prove the very low risk that results?

If this is exactly the sort of damage the activists have warned about, then the conclusion must be that it causes no more damage than a solitary tree falling down if no one is there to watch it, hear it or sense it.

Either way, Frack On! Hopefully some Shale Gas will be produced. Meanwhile, wind turbines still mince birds, but are unreliable for other purposes, and we don't know about the effects of their bad vibrations on worms or whales.

Tomo pray tell us when you stop using the word "earthquake" for low intensity events that are generated in exactly the same way as damaging earthquakes? Don't you think deliberately using a different word might obscure any possible risk of a possible future more damaging quake? I don't recall hearing a news item on Lancashire seismicity (even from the BBC) that hasn't been accompanied by a statement about their relative indetectability.
Your comment regarding geophones being able to detect footfalls is also misleading because microearthquakes can be detected over areas of square kilometres, whereas, from my experience helping students with their geophysics undergraduate projects, footfalls can only be detected at distances of less than 10 metres.