The Sherwood Sandstone which is visible in some places at the surface, and in rock core from Northern Ireland and central England, is porous and has a relatively high thermal conductivity, allowing for efficient heat transfer within it. It is considered likely that the deeply buried sandstone aquifer below County Antrim contains naturally occurring hot water (potentially around 70 degrees C) at depths of 2-3 km.   

A passive seismic survey uses distant earthquakes originating from regions such as the Mediterranean, South America, and Asia to enable us to image and ‘scan’ the underground rocks at significant depths. 

Scientists install a seismometer (the device used to detect earthquakes) in a small hole approximately 80 cm deep and 30 cm wide. The equipment is powered by a solar panel and it passively collects seismic energy which has passed through the rock layers. As is the case for all these surveys, no electrical current is transmitted into the ground, no electromagnetic fields are emitted, and no noise is created. The equipment is sealed, portable and does not impact the environment.

A total of 26 stations have been installed in County Antrim. The equipment remains in place for approximately 18 months, which allows a sufficient time to record enough earthquakes to analyse the subsurface with good accuracy.

A gravity survey measures variations in the Earth's gravitational field at different locations across an area. Analysis of these measurements allows researchers to infer information about subsurface geology by detecting density contrasts between different rock types. This information can be used to identify features like faults, buried structures, or changes in rock types based on their differing gravitational pull.

The instrument used to measure gravity is a gravimeter. Once placed on a level surface the device gives a reading to the user. The equipment is portable and does not impact the environment. For the Antrim area, around 600 measurements were recorded during the summer of 2025. 

 An MT survey involves the laying out of four 50-metre-long, plastic-coated wires on the ground and burying four small sensors (electrodes) in shallow holes. The equipment is left in place for about 48 hours (two nights). The equipment passively collects data: no electrical current is pumped into the ground, no electromagnetic fields are emitted, and no noise is created. Check out Duygu's blog to find out more about how we collect and use data from this type of survey to image the subsurface. 

MT stations were deployed at around 120 locations in County Antrim in summer 2025. 

A seismic reflection survey involves a specially designed ‘vibroseis’ truck (slightly larger than a bin truck) which stops every few metres along a designated road or off-road route and lowers a pad onto the ground. This pad vibrates the ground for several seconds to direct sound waves into the Earth. Small receivers that have been placed along the route pick up the reflections of the energy waves as they reflect off the underlying rock layers and structures. These waves move through different rocks at different speeds (due to their composition), building up a picture of the structure of the subsurface.

There is currently no confirmed schedule for this survey, which will take place along roads, but we will be in touch with local residents and communities well in advance of the work to discuss the survey and answer any questions. There also will be further information and updates posted here and on social media.