Since 13 September, the State of Geneva and the Services industriels de Genève (SIG) have been conducting a geothermal exploration survey. Geophysical measurements are being taken throughout Geneva Canton and neighbouring France, including on the CERN sites.

The aim is to map the subsurface in order to confirm its geothermal potential. Vibroseis trucks will spend six weeks criss-crossing the area. CERN has agreed for the measurements to be carried out on its sites during the nights of 18 to 20 September.

Sound waves will be sent from the surface into the ground every 30 metres and will propagate through the zone being measured. Their echo through the geological layers will be recorded by sensors, enabling the geologists to produce a 3D image of the characteristics of the subsurface.

This data collection and the resulting mapping are essential for both Geneva Canton and CERN, and will directly benefit many civil engineering projects, such as the Future Circular Collider (FCC).

The trucks' measurement points have been carefully chosen and agreed in advance and are indicated in orange on the site map (yellow dots = geophone locations; dots inside circles = soundwave application points rejected by the Organization). Each orange dot shows where a truck will stop and apply vibrations for one minute. The survey will cause minimal disturbance, as the vibroseis trucks are equipped with a new technology that reduces the noise and intensity of the vibrations that can be felt.