25 Mar 2026
We set out some of the key conclusions from Professor Haszeldine’s statement in this document. The full statement is available here.
Friends of the Earth obtained this statement in view of the ongoing application for low-volume fracking at Burniston, and following government minister comments downplaying the seismicity risks from low-volume fracking, made in December 2025. The government subsequently confirmed in January 2026 that they are reviewing the evidence base on seismicity risks.
Hydraulic fracturing, or fracking, involves the injection underground, often in several stages, of volumes of fluid down a drilled borehole to increase or improve flows of oil or gas. This process can change and increase existing stresses on rocks and so trigger seismicity, such as earth tremors and earthquakes. Professor Haszeldine describes the current UK system for regulating fracking processes, as “illogical”. There is a loophole, given the definition of associated hydraulic fracturing in legislation is concerned with high volume fracking only. This means that “unconventional oil and gas can be pursued using acidization or small volume fracking under the guise of conventional hydrocarbon exploration and production.”
There are multiple different versions of fracking processes. These include:
- the process known as high-volume fracking, which was carried out by Cuadrilla in Lancashire in 2011 (at Preese Hall) and 2018-19 (at Preston New Road);
- low-volume fracking, also known as proppant squeeze. Low-volume fracking was also carried out at Preston New Road, and it is now being proposed at some sites in England, including currently at Burniston in North Yorkshire.
- acid fracturing, whereby small volumes of fluid are used to push acid into the rock formation. This has been used at Horse Hill in Surrey. Seismicity was recorded at Horse Hill following the use of this technique.
Following the earthquakes triggered by Cuadrilla at Preston New Road in September 2019, the government introduced a moratorium on high-volume fracking in England, saying that it was not possible to accurately predict if earthquakes would occur.
‘High-volume’ is currently defined in legislation as being when more than 1000 cubic metres of fluid is injected in each stage of fracking. However, in its Preston New Road operations in 2019 (at PNR-2), Cuadrilla used less than 1000 cubic metres of fluid in all stages, and earthquakes were triggered. But the current legislation means that its operations would, under current law, be regarded as ‘low volume’ fracking and so not covered by the moratorium.
According to Professor Haszeldine, the evidence from Lancashire shows that earthquakes from high-volume fracking and low-volume fracking are “equally large and equally unpredictable”. He states further: “It is therefore clear from what happened at PNR, that “small” fluid volumes, injected for the purpose of fracking the rock to produce hydrocarbons, can cause seismicity if the geological setting is susceptible and already stressed close to the point of fracture.”
The opinion of a leading geologist that low-volume fracking can carry the same seismic risks as high volume fracking, stands in contrast to claims previously made by the Minister of Energy Security and Net Zero, Michael Shanks MP, that “the evidence base is not there at the moment to suggest that low-volume hydraulic fracturing activities have the same associated risks as fracking for shale gas”.
Professor Haszeldine’s statement explains that low-volume fracking is also intended to form new fractures in the rock, and carries risks of triggering an earthquake. Indeed, the volumes of fluid proposed for use at Burniston are higher than those used by Cuadrilla in the week leading up to the highest recorded earthquake triggered in 2019.
This means that the risk of seismicity, such as earthquakes, induced or triggered from the proposed operations at Burniston “cannot simply be ruled out”.
Professor Haszeldine’s view is that the loophole in the current regulatory framework for hydrocarbon fracking should be closed. He endorses an evidence-based definition, such as that proposed in a study by Zalucka et al (2021), which focusses on the effect of the process, rather than a volume-based definition. Such a definition would cover low volume fracking, and acid fracturing. There is evidence that both of these processes carry the risk of earthquakes.