Scientific report published

BGS submitted the report ‘Recent scientific advances in the understanding of induced seismicity from hydraulic fracturing in shales to the Department of Business, Energy & Industrial Strategy on 5 July 2022. The report was prompted by a Government request for BGS to conduct a review of science about seismic activity associated with hydraulic fracturing of shales to extract hydrocarbons, focusing on work published between November 2019 and the present.

BGS was requested by the UK Government to address six questions related to recent scientific research on the hazard and risk from induced seismicity* during the hydraulic fracturing of shale rocks. More information about these questions can be found in a published letter from the Secretary of State of the Department of Business, Energy & Industrial Strategy.

*induced seismicity: earthquakes that are caused by human activity, such as hydraulic fracturing and mining.

In order to answer the questions set out by the Secretary of State of the Department of Business, Energy & Industrial Strategy, the report draws on existing data and peer-reviewed research from academic journals and information from relevant technical reports from regulators and public bodies. This includes:

• published examples of induced seismicity related to hydraulic fracturing
• analytical and numerical modelling studies
• geological investigations
• hazard and risk assessments
• our wider understanding of earthquakes in general

No drilling of any further test wells or seismic monitoring took place.

This report has been externally peer-reviewed by independent experts within and outside the UK. The peer-review process was required to independently assess the quality and validity of the work.

The report set out to answer the questions set out by the Secretary of State for the Department of Business, Energy &Industrial Strategy. The report also sets out recommendations where further study is needed.

This report concludes that forecasting large magnitude earthquakes and understanding the mechanisms behind earthquake occurrence remain a scientific challenge. This is the case for tectonic, natural and induced earthquakes.

This report also concludes that methods have been developed that use geological and geophysical data, including real-time analysis of operational data. These methods may help evaluate the potential for induced seismicity and therefore better manage risks both before and during hydraulic fracturing operations. More work is needed to develop these methods and incorporate them into risk assessments. Further research to bring new insights that may reduce uncertainties and improve the mitigation of risks is also required.

A full summary and further information about the scientific content of the review is included within the report.

The report submitted to the Department for Business, Energy & Industrial Strategy answers six specific questions from the terms of reference related to recent scientific research on the hazard and risk from induced seismicity during hydraulic fracturing of shale rocks. While this may help inform any decision about the lifting of the moratorium, our report does not make any conclusions about whether the moratorium should be lifted.

The report concludes that more measurements from boreholes in areas of shale gas potential will improve assessment of risks prior to, and during any hydraulic fracturing operations. For example, recent research demonstrates the importance of geomechanical modelling to identify the faults that are most likely to rupture during operations. These models require accurate mapping of subsurface faults, robust estimates of stress state and formation pore pressures, and knowledge of the mechanical properties of subsurface rocks.