With the Stadel-2 borehole, Nagra enhanced its knowledge of the Nördlich Lägern siting region. Stadel-2 was the third deep borehole to be drilled in the Nördlich Lägern siting region as part of Stage 3 of the site selection process for a deep geological repository. It reached a depth of over 1,288 metres.
Area west of the coral reef drilled
The new Bülach, Stadel-2, Stadel-3 and Bachs boreholes complete the overview of the geological conditions in the region. In the south-eastern part of the siting region, the Opalinus Clay shows quiet bedding,
The Stadel-2 borehole penetrated a representative section of the siting region to the west of the coral reef. The Bülach and Stadel-3 boreholes are both located in the area of the coral reef. In addition, various tests were carried out in the Stadel-2 borehole, providing valuable information on the overall picture of the geological subsurface in the region.
Earlier boreholes
Data for the Nördlich Lägern region are already available from a deep borehole previously drilled in the community of Weiach in 1983 (see photo on left). The Weiach exploratory borehole reached a final depth of 2,482 metres. As a result, for the first time, it was possible to prove beyond doubt the existence of the so-called Permo-Carboniferous Trough, which is sunk deep into the crystalline bedrock.
Investigations using so-called 3D seismic measurements – similar to probing the subsurface by means of ultrasound – revealed fault zones in the deep subsurface in the northern part of the Nördlich Lägern siting region. For a deep geological repository, the geology has to be undisturbed. Nagra therefore withdrew the other applications for boreholes in Weiach and Glattfelden that had been submitted as part of the 2019 – 2022 deep borehole campaign. No new findings were to be expected.
Find out more about the Weiach exploratory borehole in Technical Report NTB 88-08.
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Further deep boreholes
Bachs-1 borehole
The Bachs borehole was the fourth deep borehole to be drilled in the Nördlich Lägern siting region as part of Stage 3 of the site selection process.
Bülach borehole
Bülach was the first deep borehole to be drilled in the Nördlich Lägern siting region as part of Stage 3 of the site selection process for a deep geological repository.
Stadel-3 borehole
Stadel-3 was the second deep borehole to be drilled in the Nördlich Lägern siting region as part of Stage 3 of the site selection process.
Trüllikon-1 borehole
The Trüllikon borehole was the first deep borehole to be drilled in the Zürich Nordost siting region as part of Stage 3 of the site selection process.
Marthalen borehole
The Marthalen borehole was the second deep borehole to be drilled in the Zürich Nordost siting region as part of Stage 3 of the site selection process.
Rheinau-1 borehole
The Rheinau borehole was the third deep borehole to be drilled in the Zürich Nordost siting region as part of Stage 3 of the site selection process.
Bözberg-1 borehole
Bözberg-1 was the first deep borehole to be drilled in the Jura Ost siting region as part of Stage 3 of the site selection process.
Bözberg-2 borehole
Bözberg-2 was the second deep borehole to be drilled in the Jura Ost siting region as part of Stage 3 of the site selection process.
Work report
