Lancashire fracking earth tremor was like “dropping a bag of flour on the floor” – government report


A report commissioned by the government has compared recent fracking-induced earth tremors in Lancashire to doors slamming and falling frying pans.

The research, published today by the University of Liverpool, likened the largest tremor recorded so far at Cuadrilla’s Preston New Road site to dropping a 1kg bag of flour on the floor from the height of a kitchen counter.

The report looked only at the equivalent vibrations that would be felt at the surface. It did not examine impacts of seismic activity on the borehole or the integrity of the well. Anti-fracking campaigners in Lancashire have described it as “pseudo-science” and “an attempt to distract the public with childish comparisons”.

Cuadrilla’s fracking operation at Preston New Road has caused 36 small tremors since pumping began on 15 October 2018. They happened on 13 days and the company has stopped operations because of seismic activity at least three times. DrillOrDrop tremor tracker

vibration from a bag of flour

Extract from University of Liverpool report on vibrations from a bag of flour falling to the ground, likened to a 1.1ML earth tremor

According to the report, vibrations from the largest tremor so far, (1.1ML recorded on 29 October 2018) would be the equivalent of three pans or the 1kg bag of flour dropping to the floor.

A 0.8ML tremor, which was recorded on 26 October 2018, was likened to vibrations at the surface of one person jumping.

The 0.5ML threshold at which fracking must stop under the government’s traffic light system, was compared with vibrations from mixed traffic on a busy road or slightly less than that from a door slamming.

Smaller earth tremors recorded near the site were compared with closing a window, a delivery van arriving or a washing machine on spin cycle. Seven of the examples involved dropping items to the floor but did not specify the type of floor.

The University of Liverpool said the report was commissioned by the Department of Business, Energy and Industrial Strategy (BEIS) but paid for by the university. The research was carried out by the School of Environmental Sciences. One of the authors, Ben Edwards, contributed to Cuadrilla community newsletter, distributed to Lancashire homes last month.

The report said the purpose was to:

“Provide a context to induced seismicity and the associated traffic light system (TLS) for hydraulic fracturing operations in the UK.”

It gave results from 39 scenarios, ranging from a tremor of -0.4 (bus passing on the opposite side of the road) to 2.1 (a toddler playing on a wooden floor). It acknowledged that earth tremors might be more likely to be felt in quiet areas or at night than the vibrations from the examples it gave.


The report’s findings were dismissed by the campaign group, Frack Free Lancashire. A spokesperson said:

“It is very interesting to see how these academics have passed their time, but having studied their findings, we can’t see where they look at the potential impact of seismic events on the well bore underground.

“The larger seismic events (1.5Ml and 2.3Ml) at Preese Hall in 2012 resulted in ovalisation of the well bore over a considerable distance. In that context, whether the size of the quake involved is the equivalent on the surface of a honeydew melon dropping is wholly irrelevant.

“We need a proper informed debate on these issues and not pseudo-science which ignores the relevant issues and attempts to distract the public with childish comparisons.”

In a guest post published by DrillOrDrop yesterday, engineer Michael Hill said:

“The industry is endeavouring to focus the media and public’s eyes on “felt” seismicity. It is talking about the level of earthquakes that actually shake our houses.

“But the risk at the moment is not to construction above the ground but to what lies below: the wellbore itself.

“We do not know the intensity of the ground movement at the borehole but it is immediately clear that the intensity at the wellbore must be greater than at the surface.”

When did Cuadrilla last frack?

The report is dated 6 November 2018, two days after the most recent seismic activity recorded near the site by the British Geological Survey (BGS).

This was a 0.7ML event on 4 November, which happened when fracking was not taking place and was described as a trailing event. DrillOrDrop understands that Cuadrilla had not fracked for 48 hours before that event. This was a mini frack on Friday 2 November 2018.

Since the 0.7ML event, the BGS has recorded no seismic activity in the area (BGS online data). Cuadrilla reportedly told a meeting last night of the Preston New Road community liaison group that it did not frack last week (5-10 November 2018).

DrillOrDrop asked the company to confirm this. A Cuadrilla spokesperson would not comment on the meeting until formal minutes were published. The spokesperson previously said:

“With regards to our operations at Preston New Road, we are continuing to test our exploration well in Preston New Road, Lancashire, including testing the responsiveness of the shale to fracturing. We are also analysing the recent natural gas flow at the surface and other data which is available to us following the start of our hydraulic fracturing programme last month. However, we are not giving a stage by stage update on each frac.”

73 replies »

  1. London gets lots of human induced felt seismic events every day, regularly, at just a few minutes separation. . Even in expensive real estate areas such as Piccadilly. As well as at the Houses of Parliament. Let’s shut down London – clearly it is unacceptable to have so much human indiced seismic activity, that is above natural baseline, that is measurable & felt at the surface. For futher information see seismic monitoring in London.

      • By the way, there will be a shortage of flour this year due to the effects of climate change on our weather, so stop wasting it on pointless industry blurb…..

  2. “The larger seismic events (1.5Ml and 2.3Ml) at Preese Hall in 2012 resulted in ovalisation of the well bore over a considerable distance.”

    Technically I have a couple of questions regarding this finding / comment:

    What distance was this considerable distance? How did they physically confirm the “considerable distance”? If they couldn’t run tools into the casing due to “ovalisation” how could they confirm the length of pipe affected? Were they able to run a caliper through the ovalised section?

    Clearly there was an obstruction due to reduced casing internal diameter at Presse Hall. However well integrity was not impacted according to reports.

    Severe seismic activity i.e. earthquakes of significant size can potentially damage well casing however the failure mechanism is total parting of the casing. Studies for an operator in Uganda did not find any cases of earthquakes causing well failure globally. Another company I worked for drilling in a potential earthquake area (6-8) also undertook a study for insurance purposes and risks were found to be very low and no precedent of well failure although there had been very large earthquakes in the area.

    Wells are much more likely to fail in salt sections due to movement of plastic salts such as in the Zechstein in the Southern North Sea. And these wells are designed for 1psi/ft overburden with 2 concentric strings of casing across the salt sections.

    Personally I believe the casing ovalisation at Preese Hall was much more likely to have been caused by pressure differential across the casing where the differential during or after pumping exceeded the design collapse rating of the casing where the wall thickness was on the thinner wall of the +/-12-1/2% design specification.

    The only issue caused by this casing ovalisation was financial loss to Cuadrilla.

  3. For this experiment to be valid, and to remain consistent with previous attempts to patronise Fylde housewives with a bag of spuds, the scientist conducting this experiment ought to have dropped his bag of flour into a very large bowl of jelly and measured the ground motion intensity. I think the government need to know that most housewives in Fylde are aware that a hard floor is not an acceptable food substitute for thick surficial deposits of boulder clay, sands, gravel, marine deposits and peat.

  4. Shame on DoD!!

    Missus now on strike in the kitchen, refusing to handle dangerous items such as a bag of flour in case she unleashes Armageddon. By a strange irony that will reduce local gas consumption whilst she has organised a trip out to M&S to stock up on bread and cakes, so, over the horizon and we can bask in the “knowledge” we have done our bit! Just like sending plastic to China.

    She was talking about a trip to London until she realised that the Tube was banned because of the seismic forces it unleashed daily, and didn’t fancy walking when she realised she would need to hurdle over numerous persons glued to the ground.

  5. No wonder Liverpool University dropped out of discussions regarding water testing for Fylde residents on samples around Pnr!

    By the way, Lancashire County Council have their own laboratory on Preston Docks paid for by residents. Our requests to them were likewise unsuccessful!

    Shame on them both!

  6. I’m sure Liverpool Uni feel that it’s of vital importance for the govt to know the seismic effect of dropping a variety of items of shopping on the floor and have been suitably paid for doing so. The questions that I’d like answered though, preferably by experts in geology and seismicity, is what relevance do all these seismic events (the real ones, not the shopping) have with regard to drilling and fracking oil and gas wells; what impact could it have on well integrity in both the short and long term; what impact could it have in the longer term with regard to flow paths for frack fluid, produced water and gas; how important is it to have a TLS and what level should this be set at – at the stage of exploration we are currently at in this country; what size seismic events will start to have a material effect at the surface.
    As far as I’m aware, these points have already been addressed by experts, although clearly there will be a range of opinion. Perhaps those experts could also assess what important information has been added by this study and what it has contributed to effective regulation of the fracking industry?
    Please note, as I’m no expert, and neither are the majority of commenters on this blog, I’m only interested in the considered opinion, backed by evidence, of experts in these fields, preferably those not paid by the O&G industry to have one particular opinion.
    I’d also be interested to know who provided the funding for the Uni in order that it could pay for the study itself out of the goodness of its collective heart.

      • Peter
        Mike is a chartered electrical engineer, so I am not sure he fits the bill as a competent geologist, rock doctor et al.
        Me neither ( chartered mining engineer )

        • That raises a valid point: Who is most qualified to answer such questions? The required expertise crosses boundaries, so it would take either experts with the necessary range of qualifications, or a collaboration of those who do. What is not particularly helpful is people making a judgement based on limited evidence or from a single perspective, which doesn’t encompass every aspect. Obviously not easy, but surely vital before risking the sort of seismic damage from the O&G industry in places like Oklahoma, Groningen and no doubt others, whether from unconventional or conventional. After all, I’ve still not heard any politician or industry chief claim we should have anything less that gold standard regulation, even if their actions very much suggest otherwise.

    • Maybe refer to the Channel 4 documentary on the damage done by Gas Extraction to Groningen in Holland without any large earthquakes, just lots of smaller ones!

    • Mike Potter

      WRT your last point, likely damage from earthquakes. This information can be found on the BGS website, as damage from such events is not oil and gas specific.

      The likelihood of damage locally is likely to be there as well.

      The advantage of this data is that it has been compiled for global and UK events.

      For your other questions maybe a root round on google will work for a relevant paper. However, the data, as you can imagine, comes primarily from the oil and gas industry, or other industries interested in such seismic events ( the geothermal industry frack and cause micro seismic events ) so most studies are likely to be industry funded.

      Re the uni, I thought that Cuadrilla were paying as their web site says that they hand off the seismic data to the university.

    • Mike Potter
      Having just read the report noted above, I am happy to say that the report does not add anything to the points you raise, nor add any information that would impact existing regulation.

      The report gives examples of everyday events and their seismic footprint.

      Similar I guess to explaining safety case numbers in terms of likelihood of being killed in a car accident or being hit by lightening.

      For other information refine has a number of papers worth looking at, as per below.

      No doubt more will turn up on the back of the Preston Road experience.

      Click to access Davies,%202013%20-%20Induced%20seismicity%20and%20hydraulic%20fracturing%20for%20the%20recovery%20of%20hydrocarbons.pdf

  7. Am I right in thinking that if there is a tremor after cuadrilla have stopped fracking for the day or when they say they aren’t fracking, that they do not have to wait 18 hrs before fracking again?

    • Yes. You’re correct. They also don’t have to check for damage to the well if the seismic event didn’t occur whilst they were actually fracking. So much for Gold Standard.

  8. What about the subsidence from geo thermal in Germany then? So, we stop the Cornish drilling although Southampton has been using it successfully for many years?

    Or the wind turbines that get tipped over by the wind. We dismantle all the UK ones as a result?

    Or the solar panels which burst into flames. We remove all of ours?

    Or the coal mines where subsidence was routine? We close all of ours? Ohh, we did.

    A lot of selectivity and not much objectivity. Will need to do better with NE.

    • Jack TL
      The article quite right,y congratulates the UK on its progress so far, but is not so happy about Russia, Turkey and Saudi Arabia in terms of meeting their targets.

      Plus it looks as if they are using the same dodgy maths to say how much fossil fuel industries are subsidised.

      Another point is to,think about is …. what big oil companies are fighting to squash renewables in Saudi Arabia, or is that Saudi Arabia is subsidising itself in order to squash its own solar industry rather than export oil?

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