More tremors at Cuadrilla’s shale gas site after fracking finishes for the day

181024 location map

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.

181024 BGS chart

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 operational boundary map

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.”

73 replies »

    • Wonks Hindle
      Have you asked him? Some said the same about a Kisheny, but he is a local.
      What identifies anti frackers as locals and pro frackers as not local prior to getting evidence, other than opinion?

        • Jane C
          Not been to Blackpool since 1984.
          Too much pollution from tourism!
          Living in the shadow of a coal,fired power plant. Today’s Southerly wind means any discharge heads off to Newark, not that you could tell what with the sugar beet plant in full song ( a sweetish ammonia smell ).
          Just the chicken farm to enjoy while Lincoln enjoys the smell from the maggot factory ( supports a gentle past time and local tourism ).

    • Just wondering your same question regarding the protesters that littered the sites with rubbishes after their turning up the other day.

      • T,w. After the much lauded events at Lytham, you know, the Festival, the Gala, in fact pretty much every time the sun shines, the Green and the streets of Lytham are left covered in rubbish!
        However by the following morning all’s well again, people have cleaned up and earnt some extra cash.
        I’m equally sure the ‘sites’ you mentionhave been returned to their normal state by unpaid volunteers ready for the next arrival of dedicated Environment Protectors to augment the local community who are resisting the evil fracking industry that are now delivering the unavailable consequences of their actions, swarms of earthquakes!

        • You’re kidding Peter this Summer at the PNR site the protesters left a plastic caravan full of rubbish, car tyres and general mess for the local Council to clear up…

          • Kishsney- That was left by an infultrator to give the protectors ban press. It was cleared away eventually but yes l agree it was bang out of order to dump that cavan there and blame us local protector’s for it. We even pick up the rubbish out of the hedge that people throw out of thier cars. So get the facts right. The protectors protect. We are all local because we live in this world the frackers are destroying faster than any other fossil fuel extraction. Think what you say and do a bit of research. We are on the side of truth and a duty of care to you my neighbour.

      • That was an odd comment. I was at PNR at 10.00am last Monday morning and commented that you wouldn’t have known there were 1,200 people there just two days before. Everywhere was so clean and tidy. And before there are any arguments, 1,200 was the estimate on the ITV news. I believe the police estimate was 1,000. Either way it was a lot more than the pro frackers could muster.

  1. It’s funny how many [edited by moderator] come out in force to try and play down what’s right before our eyes…..the fracturing pressures will need to be increased for the well to be productive. The sad part is, we’ll just have to sit back and wait for them to hang themselves. Paul Tresto [edited by moderator] doing his best to waffle on to hide what we will all see happen.

    • Hello Paul Cunny – please explain your logic “the fracturing pressures will need to be increased for the well to be productive”. Fracture pressure is fracture pressure. It is a physical property of the rock. The variable is the rate the fluid is injected at. Cuadrilla want to control the frack parameters (length etc.) to the design. This is controlled by pump pressure at surface. Keeping this on the low side appears to reduce the intensity of the induced seismicity and maintain operations within the TLS. The flow rates of the wells will be known after fracking is completed and the wells are flow tested. I am not hiding anything. But I appear to understand the process and what is happening a little better than you? Perhaps it is my experience in the industry and your lack of it?

      If Cuadrilla are shut down by the TLS / Seismicity so be it. But so far they have not been. They will probably pump tomorrows frack at a lower rate.

      What will we all see happen? 1mmscfd / 5mmscfd / 25mmscfd or perhaps zero. That’s what Cuadrilla are trying to determine with these wells and their program. Even with the fracks completed to date the well could be productive?

      • Preese Hall flow results look very poor considering the amount of seismicity they produced to get those results.

        With all this bad PR from 0.5M I doubt the industry could survive any 2.6 critical magnitude quakes if Cuadrilla reached their requested threshold.

  2. Agree with Paul Tresto. And the seismic are perpendicular to the well and approximately 200 m away from the well. This is what Cuadrilla want. A 200 or 300m fracture in length perpendicular to the well.
    But whether it will produce gas is a different question.

    • A 200m-300m fracture? That’s a massive fracture. I had no idea that fracking involved such a huge cracking of the geological subsurface. In engineering, a fracture to any existent built structure is known to weaken that structure. In medicine, a fracture is understood as an injury needing treatment. The dictionary defines ‘fracture’ as ‘a breakage of bone or cartilage’ from which we get the word ‘fragile’.

      • MW

        The fracture is an extension fracture ( see ‘what is a fracture, in Learning Geology ‘’)

        That also shows the other various types of fracture ( or faults ) you can get.

        Fractures can be good or bad depending what you want from the rock ( pillering for slate mining and cleat for coal mining ).

    • You don’t seem to understand Charles’ or Boyle’s law, You’re claim above is nonsense and contradicts itself. “Fracture pressure is fracture pressure (suggesting it doesn’t change) yet you then say the variable is “only” the amount of fluid that is injected and is controlled by the pump pressure at the surface….Hmmm….silly.

      • Charles Law and Bolyes laws are gas laws of thermodynamics? How is this relevant when talking about rocks and fluids? The mechanical properties of the rock i.e. the pressure to initiate fracture, do not change. Surface pressure goes up and down with volume rate and is influenced by the pressure to initiate fracture and the pressure losses in the delivery system – in this case coiled tubing.

        [Typo corrected at poster’s request]

  3. I am not sure if the anti frackers understand this But their example of Preese Hall is a good example of worst case scenario. And what disaster or environmental conditions after Preese Hall. Zero. It has been return to normal agriculture land in the last 2 years. So if that is a worst case scenario disaster risk to secure new energy source then I think many would be happy to take that risk.

    • No TW; Preese Hall was six fracks and 50 seismic events including the two big ones…..fracking stopped as a result! This site is going the same way despite the drillers best efforts. Preese Hall has been abandoned as there was no viable commercial gas without increasing the seismicity…It is inevitable that PNR will also close and be restored to ‘agricultural’ use.

      • That is exactly what my point. The worst case disaster scenario is Preese Hall well. So even with a 2.5 ML earthquake a few house tremored, a well pipe bent and leak some fracking fluid into the rock 2 km below, the well is plugged and return its original conditions. So Preese Hall is a good example in the event of a 2.5 ML quake. Not sink hole, building falls, water stock poinrd or end of local inhabitants as portrait by the anti frackers and media.

        • Vertical. And that was the total damage impact of a 2.5ML quakes which is 200 times stronger than 0.5.
          I bet if you stand 300m away from a wind turbine during high wind and measure the seismic vibration. I bet you can get a reading of >30ML seismic.

    • Tidal energy is forecast to generate 20% of UK electricity requirements, and improved storage will see offshore wind and solar increase their electricity generation margin in the coming years from 28% in the second quarter of 2018. This means the UK requirement for gas will decrease in the coming decade or two. Coal/Bio are on their way out as unacceptable CO2 emitters.

      • All intermittent renewables will require base load Gas to be viable.

        As for your improved storage, let’s hear it…

        Tidal at 20%, don’t buy that one. Look at the figures for Swansea tidal lagoon at a cost of £1.3 Billion for a small amount of electricity. The Swansea local Council are happy to invest £Millions in foreign shale industries but not their own tidal lagoon???

      • LTGL
        The Tidal energy produced by Scotrenewables always seemed the way to go, as it does not require large lagoon or tidal barrier to make it work. Good luck to them and I hope they continue to get investment.

        Those big projects are hard to get off the ground and ( as per hydroelectric in Brazil ) open to massive payola in countries further down the corruption league than the UK, and here, likely to cost a few billion before the first spade of earth is dug ( see HS2 ).

    • Yes there was increased toxic samples from the Creek down stream of Preese Hall. Look at your nuclear stats and see what happened down stream of this site. They also stopped monitoring the site. And yes they did restore it 2 years ago and none of the trees planted have grown and the field it was in is still a lake. How is that any good?

      • Netty
        What nuclear stats do you refer to.

        Over here in well wooded Notts and West Lincolnshire there are plenty of old oil well pads that have been restored.

        Some are woods, and some are in the middle of ploughed fields ( today … potatoes a few weeks ago ), so Preese Hall sounds interesting.

        There must be a reason why a well that did not do much ( certainly not years of oil production as per the wells above ) has resulted in a lake and dead trees, and maybe nothing to do with the well.

    • ‘I am not sure if the anti frackers understand this But their example of Preese Hall is a good example of worst case scenario’

      I am not sure if any pro frackers understand the following logic.

      As 6 small fracks caused the second largest recorded known earthquake from fracking in shale then hundreds of fracks in similar geology could cause larger events either from individual treatments or from the cumulative effect of hundreds of fracks.

      That is an unnecessary risk for a dirty, dangerous, expensive fossil fuel that the UK does not need for energy security.

  4. Dear Ruth –

    I’ve just heard via Facebook that Cuadrilla have all along had an agreed contingency with the EA/OGA that they may cause earthquakes up to 3.1mag, and above. They might cause them above 3.1, without necessarily having to pack up and go home. This is sketched out in a ‘Microseismic Monitoring – induced Seismicity Mitigation’ paragraph on page 2 of their Hydraulic Fracture Plan (HFP). This paragraph describes how the traffic light system up to 0.5mag works, then goes on to say:

    /”Should seismicity occur at or above the red 0.5 ML level then a vibration monitoring array will be utilised to assess the impact in accordance with BS7358-2. The measurement recorded by the vibration monitoring array and traffic light system will then be used to assess the calibration of the ground motion prediction model (14) and amendments applied if required. Cuadrilla are anticipating that the horizontal well bore, or the area intended to be hydraulically stimulated, will encounter a number of small faults. (9) Modelling a worst case scenario (direct injection into a predicted or unpredicted critically stressed fault) and using 2000 m3 stages the upper bound estimate for maximum magnitude possible would be 3.1 ML (8) , which is considered to be a very low likelihood (10). If vibration occurs in excess of 3.1ML and or PPV of 15 mm/s (as referenced in BS7358-2) due to injective operations, which is considered to be a very low likelihood, then future injection operations will be altered to mitigate below the PPV 15 mm/s level by adjusting fluid volume, rate, pressure, and or injection point. Where possible TLS data will be co-processed with any available BGS data, event magnitude determination will be calculated using the BGS methodology.” /

    What does this mean? Does it mean that anything could happen – it can’t be predicted, or necessarily prevented. Just that certain procedures will be implemented if this or that happens, but fracking can continue anyway?

    How is it that the traffic light system was presented to the public as some kind of fail safe reassurance, as if fracking would actually stop if the tremor got to 0.5mag?

    The person who posted the Cuadrilla HFP onto FB this evening, says this:

    /”It’s not very clear or easy for us to understand. If a red light seismic event occurs Cuadrilla do have to stop fracking, depressurise the well and undertake well integrity checks. This takes time and therefore costs, but upon confirming okay to EA/HSE and OGA Cuadrilla can then continue fracking. The tipping seismic event seems to be 3.1.// / / //Interestingly the plan states an intention to start with low pressure Frack’s building up to high pressure. We are one week in which is possibly only a couple of Frack’s in to the 45 proposed for this one lateral.// / / //This could do with someone with more expertise than me to clarify, but I’m happy to have put the Plan out for discussion and hopefully a finite explanation.// / / //The position of uncertainty is typical of the Industry and regulators and the local community deserve a better service.”/

    What was the Government meaning precisely when it put out the two statements (words to the effect of), first ‘we may consider relaxing the regulations on earthquakes’ and then ‘we are definitely not going to relax the regulations on earthquakes’? Does the Government appreciate the actual technical uncertainty under which permission to carry on is given by EA/OGA?

    I wonder if Drill or Drop can follow up on any of this?

    Best wishes, Linda Hurrell

    • I would read that as Cuadrilla’s forecast for a maximum ML of tremor cause by their operations rather an anything agreed with the regulators as a limit. They still have to use the TLS (or try to wriggle away from it using 2 decimal places 🙂 )

      • Was interested to hear this two decimal place rounding reasoning for not hitting a trigger on the TLS, particularly when BGS outline on their faq blog that industry standards report to one place. Why are Caudrilla out of step with industry practices in this regard? Is it because they put Lancashire First so measure more accurately or is it an opportunity to avoid having to follow the costly procedure for hitting a trigger point?

        • Creambrule

          There is a difference between a number reporting an event, and rounding it to 1 decimal place, and it being a trigger for action. 0.4999999 is not greater or equal to 0.5 , but 0.5 is so trips the trigger for action.

          I think the rounding up and down is a bit of mischief, it is what it is measured in, and you cannot round up and down if you only measure to one decimal point for a system with a decimal point trigger.

          So it must be measured to 2 decimal places at least to posit a rounding discussion , and, as it is a trigger for action, the rounding argument is irrelevant.

          I am sure no one worried when BGS report to 1 decimal place, but then, there was no trigger point for them to worry about.

          Or the traffic light system should be exceeds or equals 0.45( but it does not say that I note ).

          • “Magnitudes are local magnitude (ML) and are calculated to one decimal place, as is standard practice in earthquake seismology.“

            “We can confirm that a seismic event of 0.5ML was detected this afternoon.”

            Both quotes taken from the BGS blog so who is correct?


            So BGS and Caudrilla disagree on this, there is only one way to decide this – fight!

      • If they calculated their maximum using the now-doubted formula from Westaway and Younger, then it will give more than geothermal ‘pause for thought’

        Westaway 2014:

        The second of Professor Smythe’s points, however, is of the utmost importance. In principle, as a worst-case scenario, the possibility exists that during fracking operations at the proposed sites, fracking fluid will leak into the faults depicted
        (such as Fault 1 in Fig. 1 or the ‘Mid-Elswick Graben Faults, Thistleton Fault, or Larbreck Fault in Fig. 2), because this fluid might flow to these faults through the network of new fractures created in the Bowland Shale by the fracking, notwithstanding the low permeability of the unfractured Bowland Shale (see above). In principle, the presence of this fluid might then lubricate any part of any of these faults that it reaches sufficiently to bring it to the condition for shear failure, potentially resulting in an earthquake. If so, the resulting earthquake might
        (again, as a worst-case scenario) rupture the entire area of the fault; thus, since the faults depicted are all >1 km in vertical extent and at least several km long, the fault areas are many square kilometres, so earthquakes of the order of magnitude 5, at least, might thus occur. Earthquakes of this size would be readily large enough to cause damage to property and might well result in injuries or even fatalities,
        for example from falling masonry (e.g., falling chimneys collapsing onto victims). It is essential, therefore, to demonstrate that the design of the proposed projects precludes the possibility of any such eventuality.

        Westaway and Younger (2014) developed theory that enables, for the first time, the size of the largest possible induced earthquake of the first type to be calculated as a function of the volume of fracking fluid that is used (cf. their equation (A32)). The statement by Cuadrilla that this volume will be limited to 765 m3 per frack operation, if they get permission to proceed, means that the largest possible fracture that can form has a length of ~200 m; if this were to form in a single fracturing event it the resulting earthquake would have magnitude ~3.

        Westaway 2018:

        A theory has been developed for determining the “worst case scenario” earthquake feasible for a given volume of fluid injection. The overall volume injected at Pohang was roughly 12,000 cubic metres, whereas this theory requires around 1,000 times more volume to cause an earthquake as large as magnitude 5.5. This suggests that the theory needs improving, possibly to incorporate the injection pressure as well as the injected volume.

    • Linda
      Good that people are getting to read the frack plan and ask about it.

      The part you point to says that, if you are fracking at 2000m3 stages, and you inject that into a fault, and that fault is critically stressed, then there will be a seismic event. That event could exceed 3.1 but that is low probability. It is called ( in the plan ) the worst case scenario.

      Then you ask about whether it can be predicted or prevented.

      Well, the information you post talks about predicting what could happen in the worst case scenario. So yes, it has been predicted and bounded by a probability.

      Re prevention, yes, no fracking means no risk, but the traffic light system, via the actions to be taken as per the flowchart is a preventative measure.

      Re uncertainty … it looks like probability to me, but could be cast as uncertainty. I am sure that the government know about this uncertainty, just as they know about the probability ( or certainty ) of a worst case nuclear event at Heysham or a worst case plane crash around Heathrow, say. For nuclear power stations, the HSEx doc ‘ the tolerability of risk from nuclear power stations’ explains the HSEx and hence gov view on that ( any gov that ).

      Outwith the plan, no doubt events that can be felt, or could cause damage are not welcome by anyone, including industry. As it would be known who caused it ( and hence a large hurdle cleared for compensation ).

  5. Sorry Netty. Perhaps you need to take a look at the three who were recently sentenced before you say the protestors are all local. And they are not the first to be identified as migrating individuals. Moths to a flame, but no flame yet.

    PNR certainly is damaging the environment-by the vast miles travelled utilising fossil fuels by those who should know better. Diesel BMWs for starters: not only diesel but produced in a country where the car industry utilises much of it’s energy for manufacture from filthy coal. Also jolly day trips for the London “set” who need to get a ‘photo opportunity. Carbon footprints the size of elephant tracks.

    Produce and consume locally. Remove the imports of gas from all over the world and use our own. Much more in keeping with the recent UN report.

  6. No seismic activity today on the BGS earthquake website. The last Blackpool “tremor” was just before midnight last night. AQ05 at Staining shows very little seismic activity so it would appear that Cuadrilla have taken the day off or are doing something other than “fracking” in the well.

    Did the gate antis hear the pumps running today? Or was it all quiet today?

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