Starting with the exploration phase (installation of the drilling site, sinking of the borehole, test stimulations), baseline monitoring will help to detect any earthquakes near the project site and make it possible to distinguish between natural earthquakes and those caused by the project. The SED will publish the recorded data in real time at this page, providing the Canton, the public, the media and also the project operator with up-to-date information. In addition, the SED will alert the Canton and the operator immediately in the event of earthquakes near the project site.

This baseline monitoring will be of most use in the geothermal project's exploration and stimulation phase (not yet authorized). In the enhanced geothermal system (EGS) solution that will be rolled out in Haute-Sorne, the permeability of existing crack networks in the geological underground will be increased by injecting highly pressurised water to trigger a large number of small earthquakes. While EGS projects are already contributing to heat and energy generation in some places, they have also triggered felt earthquakes in others. In fact, there was one case where it has been suggested that these earthquakes were strong enough to cause substantial damage (see news article on the earthquake in Pohang, South Korea).

In Haute-Sorne, the operater Geo-Energie Jura wants to prevent felt or even damaging earthquakes from occurring with a comprehensive risk analysis, continuously updated models based on newly acquired data and its patented, multi-stage stimulation method. It plans, as part of this process, to stimulate only a limited volume of rock at a time in a number of separate stimulation phases and to gradually create a geothermal reservoir of the appropriate size. This procedure differs from the one-step, mass stimulation strategy adopted, for example, for the EGS projects in Basel in 2006 and Pohang in 2017. The multi-stage stimulation solution has already been successfully tested on a smaller scale in ETH Zurich's BedrettoLab. While there is some risk of felt earthquakes during the Haute-Sorne project's subsequent construction phase (hydraulic stimulation), these are very unlikely to occur during the drilling phase that is about to start. According to the operator, the first test stimulation is not planned to take place until winter 2024/2025.

The baseline monitoring provided by the SED is regulated by an agreement with the Canton of Jura and funded by the Swiss Federal Office of Energy-financed GEOBEST2020+ project. Alongside this baseline monitoring, Geo-Energie Jura operates its own stations to locate even smaller earthquakes, particularly during the stimulation phase, and so monitor the development of the geothermal reservoir. Although this phase is planned, it has not yet been authorized.

Further information on the seismic monitoring of the Haute-Sorne geothermal project can be found on the following pages:

Project overview

Natural seismicity in the region

Seismic monitoring

List of earthquakes

Real-time seismograms

Das letzte, etwas grössere Ereignis in dieser Region, ereignete sich im Oktober 2021 mit einer Magnitude von 4.1 etwa 5 km südlich von Arolla (VS). Der Erdbebenherd lag damals in etwas geringerer Tiefe, verglichen mit dem heutigen Beben. Aufgrund der geringeren Tiefe wären kleinere Schäden nahe dem Epizentrum vereinzelt möglich gewesen. Allerdings ist die Region sehr dünn besiedelt und es wurden dem Schweizerischen Erdbebendienst keine Schäden gemeldet.

Das Beben steht wahrscheinlich im Zusammenhang mit der Fribourger Verwerfungszone, welche überwiegend in Nord-Süd-Richtung verläuft und etwa 20-30 km lang ist. Das letzte spürbare Erdbeben an dieser Verwerfungszone wurde am 29. Dezember 2018 mit einer Magnitude von 2.9 nordwestlich von Tafers aufgezeichnet.