What is a geophysical campaign?
A geophysical campaign aims to obtain reliable geophysical data in order to produce detailed mapping of the geological structures of the subsoil and to verify the presence of geothermal reservoirs. Swiss Geo Energy will carry out a campaign of this type this autumn in the Eclépens region.
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Geo2X, the Vaud company commissioned by Swiss Geo Energy for the acquisition campaign, uses trucks that transmit acoustic waves to the subsoil using metal plates that vibrate at regular intervals of 20 metres. These waves reflect off the underground layers and are detected by small sensors, called geophones, positioned on the surface across the entire measurement acquisition zone.
The vibrating trucks will only travel on roads and vehicular access routes. The sensors will most often be positioned along access routes, at the boundary between plots and, more rarely, in agricultural areas - once authorisation from the landowners has been obtained.
Where will the prospection take place?
In order to collect the geophysical data, vibrating trucks will travel through the region this autumn for a maximum of three weeks. A few weeks beforehand, surveyors and topographers will mark the planned locations for measurements. At the beginning of the campaign, these same people will place the sensors in the planned locations. Three weeks later, these same sensors will be retrieved without leaving a trace.
What effects for residents?
The amplitude of the trucks' vibrations is monitored by operators responsible for compliance with current standards. The movement of the trucks, only at night (20:00-6:00), may be felt by the neighbourhood for a maximum of 30 minutes around a vibration point due to engine noise and vibrations.
The sensors (opposite) will be planted in the ground of the relevant plots then removed approximately three weeks later. These sensors are passive, that is to say they emit no waves and collect no data except for the echoes of vibrations produced by the trucks as well as their GPS position.
