On 3 October 2018, the Oil and Gas Authority (OGA) hosted a workshop on the Newdigate seismic events of April to September 2018. The workshop was chaired by the British Geological Survey (BGS) and comprised a review of the scientific analysis of the events and a consideration of whether they were natural or anthropogenic and, if anthropogenic, whether they were caused by oil and gas activity in the area.
Experts were invited from the BGS, Bristol, Edinburgh, Imperial College and Southampton universities, the Environment Agency (EA), geoscientists from the oil companies operating nearby oil and gas fields, South Eastern Water, the Surrey County Council, the Health and Safety Executive (HSE) and the Department for Business, Energy and Industrial Strategy (BEIS). Presentations were made on the analysis of the events themselves and their geological context; possible causation mechanism linked to oil and gas activity; and the scale and timing of nearby oil and gas activities. Break-out groups discussed seismicity, structural geology/petroleum engineering and regulation.
The workshop participants concluded that, based on the evidence presented, there was no causal link between the seismic events and oil and gas activity although one participant was less certain and felt that this could only be concluded on “the balance of probabilities” and would have liked to see more detailed data on recent oil and gas surface and subsurface activity. It was agreed that the seismic event epicentres were well-resolved, with depths of 1.5 – 2km, and with some scatter deeper or shallower.
Further information about the workshop and the documents can be found here