Geophones

We install three 100Hz geophones manufactured by IMS South Africa in the deep boreholes. IMS is the world-leader in seismic monitoring in mines. Based on their experience, our geophones were retrofitted specially to meet the requirements of the Bedretto Reservoir Project: The sensors must be able to record high frequencies up to the kHz range, the sensors must be spurious free when recording seismic events from short distances and able to withstand up to 100 bar background pressure. During the experiment, the geophones will allow us to record larger seismic events (we expect seismic events with magnitudes up to M 0.5) without having clipped signals. The geophone network is extended during the experiment with some additional 100Hz geophones installed temporarily in short boreholes at the tunnel and a geophone chain installed in the injection/extraction borehole.