In order to further refine the initial results obtained during previous geophysical survey campaigns (2023–24), two vibrating trucks will shortly be travelling across a 30 km² area around the borehole.

3D reflection seismic is a non-invasive method that works on a principle similar to that of medical ultrasound: the truck generates vibrations, and the subsurface reflects these waves in different ways depending on the nature and structure of the rock. Geophones positioned at regular intervals on the surface pick up the reflected signals and record the data, enabling geologists to generate a three-dimensional image of the subsurface. 3D seismic surveying will provide a greater level of detail compared with the data acquired to date. This methodology has been recommended by the Swiss Seismological Service (SED).

The surveys will be carried out by Geo2X, a company with expertise in this field which has already successfully completed the 2D geophysical survey campaign in the Delémont Valley last April.

The surveys will begin on 14 January and will last approximately two weeks, taking place during the day (approximately 8 am to 6 pm). The lorries will mainly and preferably use public roads, primarily in the villages of Bassecourt, Glovelier and Boécourt.

Noise disturbance will be short-lived, limited to the time when the vibrating truck is passing by. The amplitude of the vibrations will be monitored and will comply with current standards, thereby preventing any impact on buildings, roads or pipework. Local residents affected by the surveys have been notified in advance.

The data to be acquired, together with that already collected through the exploratory drilling and previous measurement campaigns, will enable the next stages of the project to be planned. From a scientific perspective, this represents a major opportunity to significantly improve our understanding of the geology of the Jura. Until now, the deep subsurface has only been described with such precision on a very local scale at national level.

In March–April 2025, stimulation tests will be carried out in the exploratory borehole that was successfully drilled in the summer of 2024. Detailed information will be provided in the run-up to these tests.

As a reminder, should the results be favourable, this project could supply electricity to more than 6,000 households.