Industry

1.6ML earth tremor recorded at fracking site

190821 seismograph pnr

The largest earth tremor induced by fracking at Cuadrilla’s shale gas site near Blackpool was recorded this evening.

People living near the site at Preston New Road said they heard and felt the tremor at 8.46pm.

The tremor was described as a “loud rumble and tremble”. Cuadrilla compared it to a “large bag of shopping dropping to the floor”.

The British Geological Survey measured the tremor at 1.6 on the local magnitude (ML) scale and said it was felt by people living in Westby, Weeton, Wrea Green, Blackpool and Lytham St Annes. Cuadrilla said it measured 1.55ML.

Another tremor at 10.42pm measured 0.9ML.

Fracking was not underway at the time of either tremor. But Cuadrilla said in a statement it would pause fracking operations for 18 hours.

A spokesperson for the company said:

“Most local people will not have felt it due to its small size.

“Well integrity has been verified and we will now pause operations and continue monitoring for the next 18 hours.”

Because fracking had finished for the day, the tremors counted as trailing events under the hydraulic fracturing plan for the well. Cuadrilla must carry out well integrity checks for all trailing events with a magnitude of more than 0.5ML.

The centre of the 1.6 tremor is the furthest east of all those recorded by the BGS after fracking resumed at Preston New Road on 15 August 2019.

Since then, there have been a total of 54 seismic events. There have been tremors on all six days that fracking was carried out at the site.

190822 pnr2 tremor map

Centre of tremors induced by fracking at Cuadrilla’s Preston New Road site from 15 August 2019. Source: BGS

This evening’s 1.6ML tremor exceeds the magnitude of all the other tremors since 15 August 2019.

It also exceeds those recorded by the BGS when Cuadrilla fracked the first well at Preston New Road in October-December 2018. During that operation, there were more than 50 small tremors, the strongest of which was 1.5ML.

190822 bubble chart Refracktion

Relative size of earth tremors caused by fracking at Preston New Road since 15 August 2019. Refracktion

Cuadrilla previously caused a larger tremor. In 2011 its fracking operation at Preese Hall, also in the Fylde, induced seismicity measuring 2.3ML, prompting reports from people who felt it from across the area.

This evening Cuadrilla said:

“The Preston New Road exploration site is the most regulated and monitored site in Europe and the systems in place are working as they should.

“Minor movements of this level are to be expected and are way below anything that can cause harm or damage to anyone or their property.

“All the relevant regulators were informed and we have verified that the well integrity is intact.”

The company has posted a video online about 1.6ML earth tremors, using a glass of milk to demonstrate the impact.

Local reaction: “Living in fear” – local residents respond to 1.6ML tremor

PNR tremor tracker 2019

Updated 22/8/2019 to add revised bubble chart

39 replies »

  1. The truth is the TLS has been adopted to assess the major concerns of fracking and stimulation, the system will record a high tremor, (not earthquake) and allow the operator (cuadrilla) to take the appropriate action, which they have.
    Well Done Cuadrilla.
    A monitoring system working as it should, well integrity has been record & verified!
    See you again fracking in 18 hours…

      • the outcome of the monitor is that it works, it shows cuadrillas credibility and keeps intact its reputation regarding adhering to the guidelines set out, the TLS as discussed is to safeguard the oil operator and the communities within the vicinity, it is doing everything right, and that it just makes sense.

        The bowland shale is a lot thicker than most us shale plays and as such its characteristics are different, if tremors are not felt and other than recording these on a very sensitive monitoring system, the TLS may as well increase to a more suitable reading.

        • What credibility Eli-Goth?

          That ship sailed out of port years ago after Anna’s Road and Preese Hall!

          Since the last night’s earthquakes were both heard and felt by local residents Cuadrilla couldn’t claim the effect was down to a chef at Ribby Hall dropping a water melon!

          Oh sorry, they claimed a bag of sugar could have been dropped this time!

          I know many residents of the Fylde are challenged, otherwise they wouldn’t keep voting Tory but even they don’t believe anything Cuadrilla say nowadays.

          By the way,, what’s the latest scientific research got to say about fossil fuel extraction rates by fracking, estimates down to 20% maximum of previous figures was it? I hope there’s enough left in the kitty for site clearance and restoration!

  2. So they did check the well after, that’s reassuring, because when we’ve expressed our concerns at this level of tremor, those in the industry said it wouldn’t damage the well but they now check it. Do we need to check other pipelines like water or gas in the area?

    • Think you will find PaulaC that this was done previously as well. More a case of people catching up, than anything else.

  3. Cuadrilla likens this event to dropping a large bag of shopping to the floor, as though this were an everyday practice, possibly with benign intent. Most of us don’t make this a practice, Cuadrilla: things get broken. Don’t feel you have to keep on dropping heavier and heavier bags. Even more things will get broken. Why on earth are we going round dropping shopping bags when we don’t need to?

    • laith1720. I agree. Cuadrilla’s comparisons with dropped melons, dropped shopping bags or standing under the big one are an insult to the people who have to endure this. Maybe a dropped shopping bag would cause some sort of vibration if it was dropped right next to you. But these events are happening over 2km down. If I dropped that same shopping bag 2km away would that be be felt by the locals at PNR? No. This event was both heard and felt by them.

  4. I am severely disappoint in the BGS recent induced earthquake page.
    Last night I got in late from work, and while carrying my shopping through to the kitchen, I dropped one of my heavy shopping bags.
    Ready to apologise to Cuadrilla for a false red light seismic event, I checked the BGS website.
    It’s 8:14am and still no sign of a second 1.6 ML earthquake.

  5. I would not like to experience a loud rumble and a tremble under my home and I suspect no one would. And I have yet to encounter a shopping bag that would cause this!

      • Eli-Goth,
        Are you understanding the difference between 50 years supply of shale gas recovery forecasts and 5 years supply of shale gas?
        Quite simply it’s the difference between a viable industry, albeit one that will cause Community Breakdown and Environmental Destruction and a bankrupt industry!
        And don’t tell me the Times are spouting nonsense, you’ll probably be sued for libel!

      • Eli Goth my home is not in a former mining area, does not suffer from any form of interference causing a loud rumble to be heard or a shudder to be felt. Why should people be subject to such events? I’m sure they don’t like it nor accept it. Who in their right mind would. Not only that there is an element of unknown and unpredictability about these events. Seismic events started small and increased in both magnitude and frequency in areas where there are now serious earthquake problems caused by both fracking and waste water re injection – countries like the US and Canada. These seismic events are not caused by surface vibration but caused by underground events being felt at the surface, that is different. The expert industry geologists in the US and Canada openly admit they don’t fully understand the situation and are still learning. Indeed only recently they reported events were occurring at much greater distances from the fracking site than they expected. This will never be accepted by the public no matter how much industry and supporters seek to play down and trivialise the issue.

    • KatT

      Using the glass of milk test, we have around 50 dropped shopping bag events a day in the house. This as the container trains rumble up and down the Gainsborough / Lincoln line. 24 hours a day most days of the week. Good that some freight is by rail, but others endure hundreds of such events a day by living next to the A57.

      However, the location is a lifestyle choice, so those far from both railway line and road would be upset at such levels of activity, and indeed are as the large housing estates being built cause increased lorry traffic, although that is not forever.

      Plus ( and not your point ) Saxilby station buildings, and the houses built in the old goods yard, seem in fine fettle, with no problems with piped utilities. I look at Station buildings as good examples of the resilience of brick and mortar to low level seismic activity.

      • I agree with you to a point Hewes62 that it is one thing to choose to live with full knowledge close to a runway, train line and so on but another to have it forced upon you. However, I think there are wider issues here because experiencing vibrations caused at the surface is different to experiencing noise and movement at the surface caused by an event deep underground. There is greater risk and unknowns associated with these events as there may be further events that occur at a greater frequency and magnitude. This is what has happened in the US and Canada. Perhaps insurance companies are already starting to look at the risks involved in light of PNR and home owners may be hit with either increased premiums or refusal to insure. To me it is not acceptable for people to be exposed to this and I doubt the industry or government will ever get the public to accept this.
        Very well respected geologists such as Professor Styles have warned the industry about former mining areas, limitations of 3D surveys and not fracking within 850m of an existing fault but I have seen little evidence of the industry heeding these or other warnings.

    • Better close Heathrow then KatT. Bank Holiday next week, there will be even more rumbles and trembles over a very long flight path. Not quite as noticeable as in the days of Concorde, but a lot more frequent.

        • Different circumstances, yes. But, circumstances that people have lived with in comfort for decades, KatT. My point is that what is happening at PNR is quite within normal circumstances and is what is supposed to happen.

          They may be circumstances you dislike. I am sure lots of people living near pop concerts or in a low flying test area are not too chuffed either, but tolerance of what others do, as long as it is legal, authorised and covered by the required permits is how democracy works. Funny how the antis moan about democracy but are more guilty than other groups in trying to deny it.

          Careful with the stamping feet-don’t want to create a seismic event.

          • No Martin, it is not normal, these homeowners never suffered these rumbles and shudders before. This problem is not fully understood as even US experts admit. It is a risk that people should not have to face. It is not the same as experiencing surface vibration from dropping a bag of shopping, there is a genuine risk that these events may occur in the future or may increase in frequency and magnitude as in the US and Canada. I am sure if you asked these residents if they consider this normal they would disagree. There was no fracking when these people bought their homes. It is one thing to choose to live near a concert arena, airport and another to have a nuisance forced upon you. Indeed most people that find themselves in such an unenviable situation may receive compensation but with fracking there is a cobbled together situation, which is voluntary and inequitable.

  6. Quite. Please just stop doing our shopping for us, Cuadrilla. Nobody asked you to. I suspect you hoped for a reward of some kind. We’d like to do our own shopping from now on. Enough!

  7. Anyone got a link to the regulations which have been exceeded?

    I refer to the comment in the report that a local engineer opined that ‘the tremor was ten times stronger than that allowed under regulations’.

    But a non local engineer ( myself ) opines that the tremor has not exceeded any level allowed under regulations.

    The traffic light system has kicked in for a tremor of 0.5 or over. What we would need to look at are the studies giving the magnitude and probabilities of seismic activity within the existing traffic light system ( what maximum is predicted ) to see if the tremor falls within the expected levels. And even then, there is no legal limit.

    The traffic light system is designed to limit resultant seismic activity, it does not set a limit on the likely activity?

  8. Out of interest the longitude and latitude and depth of this latest swarm of earthquakes are all displayed on the BGS page as being virtually identical.

    Including the 1.6 earthquake yesterday evening. Yet this is pictured as being halfway to the fracking site at Preston New Road on the map on the BGS page. Any idea why this should be anyone?

    • Hi Peter

      Thanks for your comment.

      In the UK, 1 degree of longitude is around 66km (the distance gets smaller as you move towards the poles) and 1 degree of latitude is around 111km (this stays broadly constant wherever you are on earth)

      So 0.001 degrees of longitude (the smallest location measure used by BGS) is around 66m in the UK, and 0.001 degrees of latitude is around 111m.

      If we’ve got our sums right, vertical lines on the PNR map should be around 330m apart and horizontal lines 555m apart (0.005 degrees of longitude and latitude respectively)

      The 1.6M event does indeed appear to be an outlier. Earlier events are in the longitude range -2.964 to -2.975. This event, when it occurred, was 0.003 degrees east of its nearest neighbour (at-2.961) , or around 200m. (Another event a little nearer has occurred since).

      The 0.001 degree limit in the BGS figures explains why the tremor locations appear to arrange themselves in straight rows and columns on the map.

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