PNR tremor tracker 2018

181214 bubble chart refracktion

Relative magnitude of seismic events at Cuadrilla’s Preston New Road shale gas site near Blackpool. Chart:

This post tracks the series of earth tremors linked to fracking at Cuadrilla’s Preston New Road shale gas site in Lancashire.

A red event, measuring 0.9ML was recorded at 13.41 on 14 December.  It followed 7 smaller tremors which had all occurred in the previous 45 minutes.

The largest tremor to date  measured 1.5ML, recorded at 11.21 on 11 December. It followed as series of much smaller events measuring 0.1 to -0.4ML earlier that morning. Cuadrilla confirmed the day before that it had resumed fracking after a break, probably dating back to 2 November 2018.

Before the 10 December event, the most recent was a 0.7ML tremor, recorded at 16.24 on 4 November 2018, about 48 hours after fracking.

We update this post regularly to show events that triggered the red and amber levels of the traffic light system regulations.

We’ll show how the location of the events has changed. There are also links to more detailed DrillOrDrop reports about the tremors.

This post uses data from the British Geological Survey online list of earthquakes around the British Isles in the last 100 days. It also uses information from Environment Agency reports of operations at Preston New Road.

Last updated: 4 July 2019 with information released by OGA (link)

Key facts

Total events


Days of tremors


Number of times Cuadrilla says it has paused fracking


Red events

Red events are seismic activity above 0.5ML when fracking is taking place

  • 11.36 (GMT), 26/10/2018: 0.8ML (measured at 0.76 by Cuadrilla)
  • 11.30 (GMT) 29/10/2018:  1.1ML
  • 13.41 (GMT) 14/12/2018 0.9ML

Trailing events above 0.5ML

Trailing events are seismic activity above 0.5ML when fracking is not taking place

  • 10.55 (GMT), 27/10/2018: 0.8ML
  • 16.24 (GMT), 4/11/2018: 0.7ML
  • 11.21 (GMT), 11/12/2018: 1.5ML

Events measured at 0.5ML by the British Geological Survey at 13.02 (GMT) on 24/10/2018 and 18.01 on 29/10/2018 were not counted by Cuadrilla as a trailing event because the company measured them at 0.48ML.

Amber events

Amber events are seismic activity from 0.0-0.5ML when fracking is taking place

  • 14.45 (GMT), 23/10/2018: 0.4ML


There are larger versions of these maps in the Excel workbook linked below.

181214 tremor tracker

Recorded tremors at Preston New Road from 10/12 up to 14:52 on 14/12
Data:BGS, Background photo: Google Earth; Graphic: DrillOrDrop

181104a tremor tracker

Recorded tremors at Preston New Road up to 16:24 4/11/2018
Data:BGS, Background photo: Google Earth; Graphic: DrillOrDrop

181211 Location of earth tremors

Location of seismic events. Chart by Professor Roy Thompson FRSE, Professor Emeritus and Honorary Professorial Fellow Univ. Edinburgh.


1Spreadsheet of earth tremors near Preston New Road up to 14.51 on 14 December 2018 (Excel 4MB download)

18 December 2018

Cuadrilla announces it is moving some equipment off Preston New Road. Details

17 December 2018

No tremors recorded by BGS

16 December 2018

No tremors recorded by BGS

15 December 2018

No tremors recorded by BGS

14 December 2018

0.1 at 2.51pm
0.9 at 1.41pm (Red event during pumping)
-0.5 at 1.36pm
-0.3 at 1.35pm
-0.1 at 1.18pm
0.1 at 1.09pm
-0.5 at 1.07pm
-0.2 at 1.06pm
-0.6 at 1.06pm

13 December 2018

0.0 at 13.25

12 December 2018

No BGS recorded seismic events

11 December 2018

1.5 at 11.21am (trailing event after pumping)
0.0 at 10.34am
-0.5 at 10.24am
0.0 at 10.18am (amber event during pumping)
-0.1 at 10.06am
0.1 at 9.53am (amber event during pumping)
-0.4 at 9.51am
-0.2 at 9.34am
-0.1 at 9.35am

  • Cuadrilla said it had stopped fracking when the 1.5ML earth tremor was recorded. It said it would pause fracking for 18 hours.

10 December 2018

-0.3 at 10.30am. Link to DrillOrDrop post

5 November – 9 December 2018

No BGS recorded seismic events

  • EA reported on 21 November 2018 that daily morning reports have been received despite no hydraulic fracturing activities.

4 November 2018

0.7ML (trailing event occurred after pumping) at 16.24, nearest seismicity to the shale gas site

3 November 2018

No BGS recorded seismic events

2 November 2018

-0.5ML at 22.59
-0.5ML at 17.44

  • Mini frack on stage 38 with 14.3m3 and stage 35 with 14.25m3 without proppant. Flowed back stages 30 and 31 with 8.61m3 stored for reuse. Source

1 November 2018

-0.3ML at 06.50

31 October 2018

No BGS recorded seismic events

  • Mini frack on stage 37 with 13.3m3 and stage 40 with 13.3m3 without proppant. Flowed back stages 31 and 32 with 12.1m3 for reuse. Source

30 October 2018

-0.3ML at 01.37;
-0.5ML at 14.36;
-0.4 at 15.55

  • Mini frack on stage 41 using 15.7m3 and stage 39 using 15.3m3 without proppant. Source

29 October 2018

1.1ML at 11.30 (red event during pumping)
-0.2ML at11.44;
-0.4ML at 11.43;
0.0 at 11.58;
0.5ML at 18.01;
0.1ML at 21.13

  • Cuadrilla confirms that it paused fracking for 18 hours Link to DrillOrDrop post
  • Main frack of stage 32 of 119.1m3 with proppant. Flowback of 8.45m3 stored for reuse. Source

28 October 2018

  • No BGS recorded seismic events
  • No fracking activity. Source

27 October 2018

-0.3, 0.8 trailing event (fracking not taking place), -0.2, 0.0, -0.4

  • Diagnostic injection test and main frack of stage 31 of 111.7m3 with proppant. Flowback of 9.18m3 stored for reuse. Source

26 October 2018

0.2, 0.2, 0.8 red event (fracking taking place), -0.1

  • Cuadrilla confirms that it paused fracking for 18 hours Link to DrillOrDrop post
  • Diagnostic injection test and main frack of stage 30 with 142.2m3 containing propappant. Source

25 October 2018

0.3 amber event (fracking taking place), -0.1, -0.6 Link to DrillOrDrop post

  • Injection of stage 22 with 350.9m3 with proppant. Flowback of 20.62m3 stored for reuse. Source

24 October 2018

0.5 (measured at 0.48 by Cuadrilla, fracking not taking place), 0.4, -0.1, 0.1, 0.0,
Link to DrillOrDrop post

  • Mini frack of stage 18 with 10.5m3 without proppant. Flowback of 0.19m3 stored for reuse. Source

23 October 2018

0.4 amber event (fracking taking place)

Cuadrilla confirms that it paused fracking for the day Link to DrillOrDrop post

  • Main frack of 128.9m3 with proppant. 17.93m3 of flowback stored for reuse. Source

22 October 2018

No BGS recorded seismic events

  • Main frack of stage 13 of 384.8m3 with proppant. Flow back of 33.32m3 stored for reuse.

21 October 2018

No BGS recorded seismic events

20 October 2018


19 October 2018


18 October 2018

-0.2, -0.8, -0.3 Link to DrillOrDrop post

17 October 2018

No BGS recorded seismic events

  • 15:20-15:25 Mini frac using 21.4m3 of fracturing fluid without proppant Link to source information
  • 16:05-17:40 Main frack using 296.7m3 of slickwater with proppant. Flow back volume of 24.9m3 stored for reuse. Microseismic events plotted from the mini and main frac stage showed events plotting below the lateral section of the well to a depth of 96.8m and laterally to a length of 191.5m. No induced seismicity noted and no breach of sub-surface permit boundary. Link to source information Link to source information

16 October 2018

No BGS recorded seismic events

15 October 2018

Fracking starts Link to DrillOrDrop post

  • 13:00Mini-frac at Stage 1 of PNR1z well. Lasted for five minutes. No proppant was used during this mini-frack. 1.87m3 was pumped into the formation. Purpose was to measure the pressure in the shale formation when injected with hydraulic fracturing fluid. A further 15m3 mini-frac was not conducted. No microseismic events detected beyond the permit boundary. Link to source information

DrillOrDrop background articles

Cuadrilla accepted tough controls on fracking earth tremors six years ago 30/10/2018

The shadow of Preese Hall over UK fracking regulations 28/10/2018

What does a red light mean for fracking? 25/10/2018

27 replies »

  1. Are Cuadrilla still on mini-fracks?

    Do we have information for hydraulic pressures used and the timings to compare to these seismic events, anyone?

    • What is required is the “Notification” document to the HSE for the fracking phase. This details of the operational program for fracking. However it is not on the document list on the Cuadrilla website.

      The drilling phase notification is on the list:

      Click to access BSOR-Notification-PNR-11Z-Drilling-12-Apr-17.pdf

      “This Notification covers planned works up to and including installation of the frac/production casing string. Following drilling rig release, the well will be stimulated by hydraulic fracturing and then production-tested, and all works associated with that will be the subject of a separate Notification to follow”

    • I put this question to Cuadrilla last week and got a reply on Friday evening.
      The press office replied: “Sorry but we aren’t giving details on timings of any of the fractures for each day”. I also asked if Cuadrilla was now doing full fractures. The press office replied: “We are doing full fractures as well as mini ones. You may recall we estimate an average of 400m3 per stage. This isn’t necessarily all mains water as some would be rainwater we collect on site or the use of flowback fluid. FYI we assessed for permits at a higher level which was actually 765m3. The press office also said in response to my question on how many fracks had been carried out: “our OGA approved hydraulic fracture plan allows us to frac one stage per day for the first 10 days and we plan to build to 2-3 a day. However, we will not be disclosing the detail of exactly when we plan to fracture each day. At 25 October, Cuadrilla said “I can confirm we have treated 8 frac stages”
      Hope this is helpful.

  2. These tremor are normally undetectable .It only because they have very sensitive equipment near site .These tremor are happening all the time all over uk .But of cause they not talk about or registered Becaue we don,t have this sensitive equipment dotted over over U.K. Load of fake new .Anyway .No Fracking in the south of Uk anywhere

  3. Fracking requires microseismic earthquakes. It’s how gas is accessed. If you don’t like it, feel free to turn your gas off at the main.

  4. WTF comes to mind!!😡 All the dodgy shiit in this world iright now is down to Black Gold and of course the next thing will be Fresh Water!! Gee I really, really worry about what the future holds for my Son, Daughter and my Grandkids!!

    • So do I, I wonder how they’ll get keep warm on a freezing cold, windless night with only non-existent wind and solar power to rely on.

      Frack on and keep my grandkids warm!

      With appropriate regulation, just as in any industry, there is negligible risk to the environment.

  5. Liking the alliteration!
    I believe the more we report on the ‘micro’ seismic activity as ‘earthquakes’ the more the general public will start to realise ‘fake news’.
    Personally I’d not bother mentioning any amber activity as a start.

  6. A few more days, it would appear, to complete this one. If it continues to the completion as it has up to now, there will be an event having been reported with great excitement that would finish with no one having felt a thing and no issues to anyone. Then, how would the media find anything to excite the wider public?

    The key then would be what output is measured. So, still a way to go, but getting closer to something factual rather than something fictional.

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