Grimsel "In-situ Stimulation and Circulation (ISC)" project

The Grimsel "In-situ Stimulation and Circulation (ISC)" project aimed at a better understanding of hydro-seismo-mechanical coupled processes that are associated with high pressure fluid injections in a crystalline rock mass. Experiments were carried out at laboratory scale (a few centimeters) and at intermediate scale (a few tens of meters).

Flagship stimulation experiment in the deep underground laboratory

The medium-scale experiments were carried out at the Grimsel Test Site. The project was divided into three main phases, namely a characterization phase, a stimulation phase and a circulation phase. The characterization phase included geophysical and geological imaging of faults and fractures, and determination of the actual stress field by means of small hydro-fracturing experiments. During the stimulation phase, fault zone were pressurized until slip occurred, and the associated permeability creation, pore pressure propagation, deformations and seismicity were monitored. In a second step of the stimulation phase the massive rock mass between the faults was hydro-fractured, which allowed the circulation experiments to be conducted. The characterization phase was completed in 2015, and the stimulation experiments were finished by the end of 2016. The entire medium-scale experiment was finished by the end of 2017. On the basis of the results, the large-scale "Bedretto Project" is established.

The total budget of the experiment is in the order of 6.5 Mio CHF, whereby 1.8 Mio CHF were contributed by Shell donation to ETHZ and a grant by EKZ. The remaining costs are covered through the SCCER-SoE, ETHZ and UniNe.

Media reports

Geothermie: Wie weiter? (Rendez-vous, 27.06.2018, SRF1)

Erdwärme ohne Beben (nano, 09.05.2017, 3Sat)

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Research Partners: ETHZ, NAGRA, UniNe


Grimsel test site

Lab website



Fibre-optic technology encounters 300-million-year-old granite. Blog article by Benedikt Galliker. Available in English, German and French.