Shaken out of my Complacency: Fracking Earthquakes on the Fylde Coast
Guest post from Dr J.H. Lees, a concerned local resident on the Fylde Coast where Cuadrilla’s fracking operations are located
As a resident on the Fylde, I have kept myself informed about fracking and its potential harm to our local environment. I have supported the various protest groups in a moral sense, but I have never felt compelled to take any active steps…before I was, literally, shaken out of my complacency by the recent earthquake.
Until now, I had thought that Cuadrilla’s series of botched attempts to frack, showed that it would never be successful here and that it was only a matter of time before they would be forced to accept defeat. However, the recent strong shake brought with it the realisation that we do not have the luxury of just allowing things to run their course. Cuadrilla’s incompetence and obvious lack of concern for the local community may leave many of us with damaged property and polluted groundwater supplies before they admit to their failure. The wake up call of this week’s quake has lead me and many other local residents to stop being so passive and try to make more of a difference in the debate.
I was particularly intrigued to hear that the location of St Anne’s on the Fylde seem to have been shaken more violently than people who live very close to the epicentre, so I decided to investigate. A copy of an email I sent to the OGA follows:
I understand that the OGA is currently considering whether fracking should be allowed to continue at the Preston New Road site near Lytham St Annes.
I live in St Annes, approximately three miles from the well and felt the recent 2.9 tremor as a strong 3 or 4 second swaying. From conversations with people that I know who live close to the site, it appears that the tremor was stronger in St Annes than that felt close by the well. This prompted me to look into why that might be the case and soon discovered many references to ‘site effects’, ‘earthquake susceptibility’ and ‘liquefaction’.
Lytham St Annes is built on an area of sand with a high water table.
It appears that seismic waves are amplified when they pass into sandy areas such as this and, furthermore, it is the lower frequency (most potentially damaging waves) that amplify the most. This appears to tie in with the effects observed here.
I am writing to draw to your attention the high seismic susceptibility of our area as you make your deliberations. If further fracking leads to more run-away seismic events, I am fearful of the consequences for our community.
Tremors that are dismissed as ‘minor’ or ‘within model’ by Cuadrilla have a much greater impact than appears to have been considered. The 2.9ML tremor had about 250 times greater magnitude than the 0.5ML limit they agreed to. Even more alarming is the realisation that this represents a release of around 4000 times more energy than from a 0.5ML event.
Looking ahead; a 3.1ML Richter Scale tremor, that Cuadrilla is saying was in their model and, therefore ‘acceptable’ (in spite of your 0.5ML traffic light restrictions) would be even larger, having 1.5ML times greater magnitude and releasing almost DOUBLE the DESTRUCTIVE energy of their last 2.9ML quake.
A longer lasting, stronger quake such as a 3.1ML, would have an even greater impact on residents and property , particularly if it also causes liquefaction of the sand.
Please put an end to the nonsense of fracking at Preston New Road; especially when it is so close to large urban areas built on sandy soils. Our particular susceptibility to seismic activity does not appear to have been fully considered before.
As an after thought, the susceptibility of Blackpool and the Fylde to damage from seismic events (which does not appear to have been considered by the authorities), could be severely tested should commercial fracking actually go ahead. The accumulated effects of multiple tremors from several fracked wells could very well lead to liquefaction of the sand – making damage to property and infrastructure even more likely. Reports from Holland (Groningen), on the devastating effects of gas extraction, show how multiple ‘small’ tremors can add up to a huge mess.