Second amber tremor at Cuadrilla’s fracking site

181024 fence art Pip Hockey

Fence art outside Cuadrilla’s shale gas site, 24 October 2018. Photo: Pip Hockey

Cuadrilla confirmed this evening there was a 0.3ML earth tremor during fracking this afternoon at its Preston New Road shale gas site near Blackpool.

It was classed as an amber event under the seismic monitoring regulations, known as the traffic light system.

Cuadrilla said it expected that fracking would continue as planned tomorrow.

This is the second amber event detected during fracking in the past three days (more details). It is the third consecutive day of seismic activity near the site and the 12th tremor recorded since fracking began on 15 October 2018.

181025 BGS chart

Extract from British Geological Survey record of seismic activity in the British Isles since 18 October when the Blackpool tremors began.

Following an amber event, Cuadrilla is allowed to complete the fracking operation with caution. Pressure in the well has to be reduced by flowing back liquid. The integrity of the well has to be checked and operations continue, possibly with reduced pressure.

181025 location map

Graphic showing progression of tremors over time. A is the first tremor (18 October) and L the most recent (25 October). Tremors C and E are in almost the same location. Source: Robin Grayson

Cuadrilla said this evening:

“People should remember and be reassured that anything registering between 0 and 2.0 on the Richter Scale is generally categorised as a micro seismic event, far below anything that could be felt at surface or cause damage or harm.

“On average around 8,000 micro seismic events are detected in the world every day and very rarely reported in the news. These are truly tiny movements and without the sophisticated monitoring in place at PNR, they would in all likelihood not be detected.

“We’re comfortable that the traffic light system is working as it should. Everything so far has been within our operational expectations, in line with the work we’re carrying out and reported appropriately as part of the Oil and Gas Authority’s traffic light system. All the relevant regulators have been informed.”

The tremor was recorded on the British Geological Survey online list. Initially it was registered as a 0.6ML.

181025 BGS chart2

The site went temporarily offline and when it came back the tremor had different location coordinates and a 0.3ML magnitude. The BGS said:

“No events have been removed from our web pages. However our web pages are linked to a database that contains information about all the seismic events that we detect and locate. If the database is changed the web pages will reflect this change.

“In this case, the event at 14:59 UTC on 25 October was still being analysed and the location and magnitude had not been finalised when the web pages were updated. This resulted in incorrect information appearing on the web pages for a short period of time. The correct location and magnitude for this event are now as listed here.”

BGS webpage on seismic activity at Preston New Road

What does a red light mean for fracking?



37 replies »

  1. And they have just triggered a 0.8 tremor and so it goes on, no one should be surprised after Preece Hall, no one that is apart from Cuadrilla who are too arrogant to realise this would happen.

  2. It is likely that Cuadrilla completed today’s frack – hence the 0.8 tremor. So Cuadrilla will resume as normal tomorrow morning (18hrs later) assuming no objections from OGA / HSE etc. and no additional red light tremors. I wonder how much time, if any they have lost? Well integrity has already been checked okay.

    “A spokesman for Cuadrilla said: “It is reassuring that the monitoring and traffic light system is working as it should.

    “All the relevant regulators were informed without delay and we have verified that the well integrity is intact.

    “As per the hydraulic fracture plan in place at Preston New Road, work will now pause for at least 18 hours and is expected to recommence on Saturday morning.””

    I had my doubts about the TLS knowing how it came about but it would appear that it is working out okay and doing it’s job albeit the thresholds are far too low.

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