New Quakes off Blackpool 25th August 2013
01/09/2013 updated 18/09/2013
BGS lat/long of epicentres mapped on google
Epicentre imposed on DECC oilfield map (approximate)
Perhaps because of the Bank Holiday weekend, the press didn't work on the two earthquakes recorded with epicentres off the Fylde coast. They just printed the facts and a couple of comments.
The Mail, of course, felt it necessary to insert in its report:
"Last year it was suggested that fracking tests in the region had caused tremors in Blackpool."
Rather more than suggested, the proof was clear except to the fracking risk deniers, of which the Mail is the cheerleader.
The Mail was also keen to point the finger at prehistory. A spokesman for the The Irish National Seismic Network said the quakes were probably caused by stresses built up from the weight of glaciers covering land during the Ice Age. However INSN director Tom Blake also said said it was unusual that the earthquakes - measuring 2.5 and then a stronger 3.3 on the Richter scale - happened in the Irish Sea.
Glen Ford from the British Geological Survey said it could have been ‘quite alarming’ and added: ‘Not many people experience earthquakes in the UK. There are only two or three of them a year of that size.’
Back on 1st April 2011, immediately after the first major felt tremor at Blackpool now known definitively to have been casued by fracking the Preese Hall well, the BGS seismic supremo Brian Baptie was quick to issue a statement that the tremor was a remnant of the Ice Age. He told the BBC ""The movements are a relic of a post-glacial uplift left over from the last ice age." He also said (contrary to anecdotal experience) that it would take a 'quake of greater magnitude to do any superficial damage.
Brian Baptie was proved wrong (including by his own organisation) when extra seismic detection equipment pointed the finger at fracking PH1 in May, when the second fracking-induced 'quake (in the meantime there were also about 50 very minor but measurable events). Glen Ford now seems to be taking a more cautious line (including predicting small aftershocks in the coming days or weeks).
So is Tom Blake also to be proved mistaken? We will have to wait and see.
What we can say is that according to the BGS data from last Sunday's 'quakes, the epicentres of both were extremely close together. Above is a map of the Irish Sea offshore from the Fylde from DECC showing offshore oil and gas permission areas and wells. Also marked is the epicentre of the earthquakes. Coincidence? I'm no geologist and don't know what exactly is going on right now on the sea rigs. But I wouldn't write the story off yet.
Now I have remapped the BGS data the epicentres both appear to be on the rightmost fringe of an area which is currently being developed for offshore gas storage caverns. Work is almost certainly going on here, and I have asked DECC for confirmation of this, and whether they intend to ask BGS to do more research on the possible cause of the weekend's quakes. This has implication not only for fracking the Fylde, but for the Halite plans for an onshore underground gas storage set of caverns near Preesall, Blackpool. Their application for planning permission was recently turned down,
however they are pursuing a judicial review of the planning inspectorate's refusal on grounds of insufficent geological data. Meanwhile they are currently carrying out survey work including explosions and monitoring of underground response.
Since writing the above I have now had information from the BGS to say that to their knowledge work has been delayed on the Gateway project and has not yet commenced, which rather rules that one out. Although it still remains a possibility to be matched against the historical seismicity of the area that oil or gas works in the Morecambe field could be linked. I doubt we shall get any further information one way or the other on that.
Although opponents of fracking have tended to downplay the seismic risk of fracking as far as earthquakes are concerned, there are still concerns about seismic events causing damage to wells (as happened at Preese Hall) and seismic events opening faults allowing migration between saline and freshwater aquifers, or indeed gracing fluid to aquifers. These concerns have not been addressed.
In any event, we can also say that to pursue fracking in the Fylde which is clearly now prone to faults moving, in particular to pursue mass fracking there would be extremely unwise. We haven't heard the last of the earthquake issue yet, I feel.
BGS warned of aftershocks, but another quake of magnitude 2.6 on the 31st August perhaps exceeded expectations.
DECC confirmed the following-
• The Gateway gas storage project has not yet submitted a Gas Storage Development Plan, and as such, no activity has taken place offshore.
• The Centrica gas field (Bains Field) closest to the published earthquake location has not been in production since 2009 and has not under taken any fracking.
• The producing Morecambe gas field (further west) has never been fracked. The earthquake was not felt on the producing platform, and there are no reports of any damages or operational problems.
• We can confirm that DECC has been in communication BGS regarding the earth tremors.
• We understand that Halite have conducted onshore seismic surveys at Preesall, under existing licences obtained from appropriate bodies including the Lancashire County Council. We are not aware of any connection between this and any other offshore facility.