Research

Two more Surrey earthquakes – second oil company says it’s not to blame

180718 earthquake chart Stephen Hicks

One of two small earthquakes in Surrey today. Source: Dr Stephen Hicks

The British Geological Survey confirmed there were two more small earthquakes in Surrey today – both in the same place as the previous cluster.

This brings to 10 the number in the county since April 2018. Before then, earthquakes had not been recorded in Surrey for 50 years.

Today’s first earthquake was just before 5am British Summer Time and had a magnitude of 1.7, later raised to 2.0. The second was at 2.33pm BST, and measured 2.7. Both were felt by residents in the Newdigate and Charlwood areas of Surrey. There were also two aftershocks.

The cluster of earthquakes has prompted calls by some local people for an investigation into any links with the local oil and gas industry. A public meeting has been planned for 25 July 2018 in Brockham, where Angus Energy operates an oil production site.

Last week, the British Geological Survey installed two seismic monitors to track the earthquakes (DrillOrDrop report). One is at Russ Hill, directly above the current best estimate for the epicentres. The second is in the Norwood Hill/Horley area, near another oil exploration site at Horse Hill.

180718 BGS earthquake data

2sLocation of recent earthquakes in Surrey. Map: BGS

“Scientifically impossible”

The main investor at that site, UK Oil and Gas, has previously refuted any connection between Horse Hill and the earthquakes. (Links here and here)

Yesterday, the managing director of Angus Energy, Paul Vonk, rejected any link with the Brockham oil site.

Mr Vonk, speaking in an online interview with Zak Mir, said:

“It is scientifically and physically impossible for us to have caused these tremors.

“Of course, tremors in an area of southern England where they haven’t been in ages, you know, is news.”

Mr Vonk said:

“Basically, the way the faulting structure works, it works from east to west. We, at the reservoir at Brockham, are working at a third of the pressure that you can actually activate faults. So we can’t do it with our current reservoir.

“But even hypothetically, if we could do it, the stresses would go east-west. The epicentre of the tremors was 10.5km south of us.”

He added:

“The BGS is doing some extra work and in time it will be proven by the authorities that it isn’t us.”

“Fascinatingly shallow”

180718 tweet Stephen Hicks

Southampton University seismologist Dr Stephen Hicks, who helped to install the new seismic monitors, said today on Twitter:

“Location, depth & magnitude confirmed – new stations allow for much better estimates, especially for depth. Magnitude 1.7 and at about 1km depth, with an epicentre location close to the previous estimates for the earlier quakes in the sequence.”

He added:

“[About] 1km depth is fascinatingly shallow if you compare to most UK earthquakes which have depths >5km in the crust. To me 1km depth suggests that today’s event occurred in the softer sedimentary strata, rather than in the underlying crystalline “basement” rock.”

18 replies »

  1. You have to ask yourself why , but without making accusations it need to be properly investigated and the precautionary principal used .

  2. So lets hear a truly independent voice saying the hydrocarbon exploration activity can’t possibly cause the earthquake. That is a very strong statement. I would not trust the company’s word. Fracking DID cause 2 earthquakes in the Fylde in Lancashire, and numerous earthquakes in America. Looks fishy to me.

  3. Of course it does to you Ian. But, please tell us where fracking is happening in the South East. If there is none, then the Fylde is as irrelevant as the largest earthquake that recently occurred in the Highlands is irrelevant.

    I understand there are pretty dramatic tunnels being constructed under London. A lot closer than the Fylde and the Highlands. Why not blame them, and close down the work based upon the precautionary principal? I think we know the answer.

    • A fine argument Mr Collyer. Very convincing indeed.

      But it is more than a little coincidental and very disconcerting that the at theepicentre of the quake swarm, the depth of the quakes (reported today by BGS to be between 300 to 700 metres) and the period when the quakes have occurred is finely aligned with activities at Horse Hill and Brockham.

  4. The Blackpool earthquakes were a LOT less at 2.3 and 1.5: the Richter scale is logarithmic so a quake of 3.1 magnitude is 10x greater than one of 2.1. So well casing damage is a real possibility.

    • Pat Smith
      The casing damage was across a fault or slip plane I believe according to the report..
      So … are any of the oil wells at the epicentre ( is where movement occurs ) or a distance from it?
      Always happy to see what the BGS come up with.

  5. Well LH, you need to check the dates a bit more carefully and the comments from the BGS. This sequence of tremors started before any work was being conducted at HH. Very convincing indeed-not.

    • Even less convincing Martin. Because we all know that’s not true.
      Are these the same obscufating arguments that you made about earthquakes connected to O&G in Holland, the USA, and elsewhere?

  6. No-because I didn’t make any such arguments. I think you have me confused with somebody else as you are confused with dates. In other life aspects that could be an extremely problematic combination! But, I understand there are tests now to solve that.

    With regard to HH, please remember although work was conducted many months ago, it then ceased and only restarted a short while ago, once further authorisation was achieved. BGS are certainly aware of that-check it out.

    Even less convincing is someone who has to make things up to support a position.

  7. Mr Collyer, Neither you nor I know whether the recent works at Horse Hill and Brockham are linked to the unprecedented earthquake swarm centred in Surrey.
    It may just be pure coincidence or it may be directly related. We dont know. for certain yet.
    But what we do know.
    1) There is a long history of earthquakes occuring in areas of oil and gas exploration which has been directly linked to the exploration, being it fracking or other forms of stimulation. See Holland, see Texas, See Pennsylvainia.
    2) Earthquakes havent occurred in this region for a very, very, long time.
    3) We’ve now had 10 in the last 3 1/2 months.
    4) They all appear to have occured between Horse Hill and Brockham at what yesteday was confirmed by the BGS as 300 to 700 metres which I understand to be the drilling depth at Horse Hill.

    It really does require further honest investigation. So rather than acting as blind apologist, making strawman arguments about construction works in London and throwing insults at genuinely concerned citizens perhaps you could suggest how the O&G industry can demonstrate and reassure us that the earthquakes are entirely coincidental and nothing to do with the activities.

    • If you hadn’t had earthquakes in the area in the last 50 million years, I’d call that a long time. 50 years since the last reported earthquake is nothing on the geological time scale.

  8. So, you ignore the fact you just wanted to misquote me! Equally, you simply want to imply that some seismic events in other countries are somehow a reference to what is happening in this region. That is certainly not proven, and makes as much sense as my tongue in cheek remarks about tunneling under London. Quite simply, the BGS is the body with the expertise and they are looking into the matter. You, and your buddies, will not believe anything the O&G industry tell you, the BGS are the expert body, so they are the ones to follow. I certainly will follow them rather than your speculation, and I have given the same advice to others who indicated they were concerned locals. When I did that recently, it was the anti sector who then produced a whole fog of speculation and nonsense-including how the Aztecs built their houses!

    You really need to check what is happening at HH, and when it started. You can do that even without asking the O&G sector, as much is in the public domain. Try UKOG site to start with. Drilling? Err, no. That was done over a year ago. Currently, HH is rechecking flow rates from what was drilled at that time, and only just started that. Quite a long way off new drilling. Indeed, the first output from that check was only transported away yesterday, as reported on DOD.

    • Ellie Gold
      I think that the BGS will consider all relevant activities in the area in question.

      The EA Report SC150027/R. ‘ Reinjection of fluids to deep geological formations, is worth a read to get a handle on the subject.

      The report notes that ‘ there are no known records of induced seismicity in England associated with conventional oil and gas reinjection activities that have resulted in contamination or damage to infrastructure’. ( section 3.1 2nd para ). This excludes HPHV fracking in the Fylde.

      Not quite saying there is no known seismic events, but as the report found no link, then either there were none, or they were so small and we did not know they hapenned.

      No doubt the BGS will expand their investigation to include some of the injection parameters noted in the report, should the quakes continue.

  9. Thank you for your detailed response Mr Collyer.
    1) I apologise if I implied that you had voiced expert opinion on siesmic events connected to O&G exploration in other countries. I understand that the O&G industry has spent many years denying any link.
    2) Your “tongue in cheek remarks” appear to be used purely to ridicule the real concerns that people have about this exploration rather than be considered input to the debate.
    3) Me and my buddies? Now what should you call me? Looking back at some of your previous posts. A NIMBY, a swampie or some other derogatory term.. Except that I am none of these. I am a chartered engineer with a young family who has been drawn into this debate by the arrogance and idiocy of the O&G companies who appear to be unconcerned about peoples’ genuine fears. I have come to the conclusion that onshore explotaion of oil and gas will have a negative effect on the enviroment and wellbeing of the local population whilst benefiting very few, most of whom will not have to endure the residual problems.
    4) I think it is perfectly acceptable to question whether there is a link between the earthquake swarm and O&G activities.
    5) I am aware of the reported timetable of works at Horse Hill and at Brockham, but thank you for your advice.

    I hope this clears this up.

    Now that you know more about me and my concerns perhaps you could reveal what motivates you to be such an ardent poster on this site.

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