Location of seismic events linked to fracking at Cuadrilla’s Preston New Road site near Blackpool. Activity today is marked with red rings. Source: Batchgeo using Google Maps
The British Geological Survey has reported a 0.5 magnitude earth tremor this afternoon near Cuadrilla’s fracking site on the edge of Blackpool. There was also a 0.4M tremor and two micro-seismic events.
Although too small to notice on the ground, the 0.5M event is the largest so far in a series recorded near the site since fracking began earlier this month.
Cuadrilla said the 0.5M tremor did not count as a red seismic event under the government’s traffic light system for monitoring seismicity. This would have required the company to stop fracking, carry out checks on the well and inform the regulators.
A Cuadrilla spokesperson told DrillOrDrop the event actually measured 0.48M and had been rounded-up by the British Geological Survey. He said the company was also not fracking at the time of the tremor. Fracking planned for tomorrow is expected to go ahead, he said.
The British Geological Survey record of UK earthquakes says magnitudes are calculated to one decimal place, which is standard practice in earthquake seismology.
A statement from Cuadrilla posted on Facebook said:
“Following on from hydraulic fracturing operations today Cuadrilla has detected micro seismic activity of 0.48ML. This is within the operating expectations and the sophisticated system of monitoring in place is working as it should. We understand that the British Geological Survey has rounded this up to 0.5ML. Regulators have been advised and we anticipate we will continue work at Preston New Road tomorrow as planned.
“As we have said before, local residents should be reassured that the monitoring systems in place are working as they should. These are tiny seismic events that are being detected by our monitors as we fracture the shale rock 2km underground and are many hundreds of orders of magnitude below what is capable of being felt much less cause damage or harm at the surface.”
Yesterday, Cuadrilla stopped fracking for the day after a 0.4M earth tremor was recorded during operations at 3.45pm.
Today’s events mean 10 of the past 12 seismic events in the UK have been near the Preston New Road well.
The seismic activity began four days after fracking started at the site. There were micro-seismic events on 18 October, followed by a 0.3M tremor on 19 October. There was a 0.0 event on 20 October, 0.4 on 23 October and 0.5, 0.4, -0.2 and 0.0 today (24 October).
Cuadrilla’s hydraulic fracturing plan said if seismicity of 0.5M or more was recorded within a defined area during fracking then the company will flush the well, stop injection and reduce well pressure. It would also verify well integrity. Cuadrilla should report the incident without delay to the Oil & Gas Authority, Health and Safety Executive and Environment Agency.
The traffic light system for seismic monitoring was introduced after 2.3 and 1.5 earthquakes were linked to Cuadrilla’s fracking operation at Preese Hall, also near Blackpool, in 2011.
Cuadrilla’s area of operation for the Preston New Road well. The red zone marks where fracking can take place. Source: Cuadrilla Resources
A spokesperson for Frack Free Lancashire said:
“The escalating magnitude in tremors caused by fracking in Lancashire is unacceptable.
“Today, a 0.5 magnitude tremor occurred. Seismicity must be monitored closely around the clock if hydraulic fracturing is allowed to continue in spite of the cluster of tremors we have seen around the toe of Cuadrilla’s well.
“Local residents are rightly concerned by these events and the fact that the traffic light system has had to halt operation just a week into the process.
“The issue is not whether these events can be felt, but whether they could be precursors to similar events that occurred at Preese Hall in 2011, which led to Cuadrilla’s performance as a licencee being questioned by the then Energy Minister, Charles Hendry.”
“The well integrity and safety of what happens underground is beyond anyone’s control, following a seismic event. This risky technology employed by an inexperienced operator – as demonstrated by the seventh tremor in as many days, causing a Red warning on the Traffic Light System, is something residents will never support and our strong opposition will continue and increase.”
Richard Marshall, an anti-fracking campaigner at Preston New Road, said:
“Cuadrilla are claiming that the seismic events are low level and residents should be reassured that the monitoring equipment is doing its job.
We do not feel reassured and our fears have been realised. We also expected seismic events. We have been explaining and proving that there are fault lines in the area and that there is a great risk to well casings rupturing. It seems that Cuadrilla are insistent on progressing to appease their investors to the detriment of the health of the people.”
Categories: Industry
DRILL OR DROP? 
So according to Cuadrilla the 0.5 event was actually of magnitude 0.48, or 95% of the amplitude of 0.5.
Firstly, what are the error bars on its estimate? I doubt if they are within +/- 5%.
Secondly, this is the first report I have ever come across of microseismicity being measured to two decimal places – however, I stand to be corrected if wrong. I trust Cuadrilla operatives will furnish counter-proof.
Thirdly, the threshold figures quoted in the Traffic Light System are given only to one decimal place. Scientifically this means that 0.451 must be rounded up to 0.5 (and conversely 0.449 would be rounded down to 0.4). If the legislation wished to express the thresholds to two decimal places then it would have explicitly state the threshold figures as 0.50, 1.00, etc. But it has not done so.
Therefore the ‘0.48’ event is, according to the legislation, a 0.5 event. Fracking should cease. Cuadrilla is disingenously trying to make monkeys of us yet again.
Why should fracking cease ? Because you think that Cuadrilla may have caused minute tremors, you cannot convert that into a fact in your own mind, even less broadcast it over the internet as a proven event. As for the comment below about a cocktail of poisons , nothing more than you use in your kitchen and bathroom on a day to day basis. Like all environmental twaddle low on facts high rhetoric , and extraordinary on philosophy. Just bear in mind that the UK suffers some 300 earth tremors per year and no we are not all being killed by them. The last recorded earth quake of any significane in the years 1884 lasted 20 seconds and did some structural damage in the Colchester area (nobody was fracking at the time !)
VERN WALK,
Taking note of your above comment , we should put our trust in what the professionals say.
Names and professional credentials are also included.
The British Medical Journal ( BMJ ) Public Health England’s draft report on shale gas extraction.
https://www.bmj.com/content/348/bmj.g2728/rr
VERN WALK,
You’re quite right to bring up about the toxic side of Fracking.
What are your thoughts on the above link ???
Amazing that some think that there is nothing to worry about as humans go down thousands of feet infiltrating the Earth with high pressures and a cocktail of poisons… may the government follow their own rules and cease the fracking….
Looks like the current swarm of seismic activity surrounds Penny Farm, the horse sanctuary where police vehicles hide waiting to be deployed at Preston New Road right trample on Environment Protectors right to protest!
How sweet!
The wall is closing in on the cracker frackers… Not long now until we get the seismic event that completes our job! Come on Egan just fire up them pumps properly, you know you’re going to have too eventually 🤣😂🤣😂
Peter its also the place Fargo Mc Cann has been seen early mornings having a brew with the police, how ironic!
Wonder what the reading would have been for the construction of Crossrail??? Or the daily operation of the London tube system??? Maybe the monitoring was less? Yes, wonder why?
Perhaps the difference is there were none there trying to excite, and the majority were more interested in progress. Ahh, but so they are in respect of PNR.
Monkeys there are. “During fracking and not during fracking” seems quite instructive to the higher primates.
Latest records seem to be heading back towards the pad, as expected. Looks pretty controlled at this stage. If they can keep within these parameters all the way back would turn out to be just about perfect in terms of control. Whether optimum in terms of gas release is a different question. Time will tell.
Thanks for your comment David.. worth reading unlike some of the constant rubbish by some of the primates on here…
The writing is on the wall for this industry in the UK. At last….!
Actually Prof Smythe’s comment doesn’t really tell us very much today. It is a discussion on “rounding” up or not.The seismic events appear to be moving east parallel with the well bore as would be expected as the fracks are being conducted back up the well from TD in a West to East direction.
This implies that the seismic events are moving further away each frack / each day from the Wakepart Fault which Prof Smythe locates 1km West of TD of the well based on his 2D interpretation (actually it looks a lot further away than 1km on the section but I am not a geophysicist).
For reference the 2D interpretation can be seen at:
http://www.davidsmythe.org/frackland/?p=551
The fault as mapped on the surface plan is the surface extrapolation of the fault and NOT where the fault is at well depth. This can be seen on the 2D section which shows it >1km away to the West from the well TD. Prof Smythe confirms this in the comments below the article. It would be better to show the fault on the plan where it is at well depth?
So these events do not appear to be related to this fault.
[Comment corrected at poster’s request]
Looks as if the tremors will continue to move up the well, away from the toe ( to the right on the map ) as fracking proceeds. No doubt an event past the toe would cause some discussion on here.
We await a red event while fracking to see how Cuadrilla Respond, but note that if 4.8 we are still in Amber for post fracking. I note the thoughts above recrounding up,or down for reporting, but as the 0.5 is a threshold for action I expect it is measured to 2 decimal points, otherwise the threshold would be 4.5 ( but only my opinion ).
However, an amber spot has turned up,on their portal. As they say they were not fracking at the time, good that it is reported ( but some questions about it appearing there of ot was truly a trailing event no doubt ).
Has Cuadrilla undertaken ‘full’ fracks yet? I thought they were trialling with mini-fracks to begin with. If they are causing 0.5 tremors with mini fracks then goodness knows what the result will be from a full on frack! Can anyone confirm this?
Yes. Around 8.
Amunguy
Mini or full on frack should be the same, you get into amber and take actions, and if it goes to red you stop.
The concerns, as noted are what happens then. Events that people can feel or not I guess.
Amunguy- surely mini or full is not the point. These tremors would seem to indicate fracturing is taking place, and doing so within the traffic light system. Gas output will be the indicator as to whether it has been enough.
I suspect the review of the traffic light scale may revise the figures upwards over time but obviously sensible to start low and go from there.
Don’t forget that the horizontal wells currently being fracked are about half the length of those required for production fracking.
Therefore only a fraction of the pressure required for production is being applied!
Peter K R
Do you mean management pressure to achieve results or actual pressure required to frack?
A horizontal hole twice the length will require the same pressure at the sleeve / shale to frack at the same pump rate as the shale fracture pressure will be the same – the rock mechanics will not change horizontally unless the geology changes. The surface pressure (pump) will be higher due to the added friction loss of the additional frack string length. Easy to calculate and no big deal.
Yes, it will be the same pressure Peter KR – probably between 10,000 and 15,000 psi, although Cuadrilla could (understandably) be taking a cautious approach until they’re able to gauge impacts. But you’re right, the laterals are nowhere near as long as for full scale production (where they could be 2 miles or more). Paul’s right about the friction though, to achieve the (same) necessary pressure at the perforated sleeve stage, when driving the sand/proppant/chemical slurry over longer lengths, requires a bigger driving force to overcome the friction. Some of the chemical agents involved in the cocktail are for lowering viscosity, hence the term ‘slick-water’.
Surface pump pressure is the lower end of 7,500 – 9,500 psi. Depends on the rate. But Cuadrilla estimate 7,500psi in their program.