The most straightforward geological situation is one of the central arguments for selecting Nördlich Lägern as the site for a deep geological repository (Explanatory Report on the General Licence Applications, NTB 24-12, Chapter 6).

The argument is explained in the report Begründung der Standortwahl (“Justification of the Site Selection” (in German), NTB 24-03, Section 5.2.3). In Nördlich Lägern, the rocks are the most quietly bedded, and a safe distance can be maintained from tectonic fault zones when planning the layout of the deep geological repository. Nördlich Lägern thus not only has the best quality of available space, but also the best conditions for preserving the stability of the site and the rock properties.

The reference report Qualitative Bewertung der 13 Kriterien gemäss Sachplan geologische Tiefenlager (“Qualitative Assessment of the 13 Criteria according to the Sectoral Plan for Deep Geological Repositories” (in German), NAB 24-23) characterises the spatial extent of the containment-providing rock zone (Section 4.1.1) and the stability of the site and rock properties (Section 4.2.1) and shows how the argument is substantiated by means of a qualitative assessment of the containment-providing rock zones based on pre-defined criteria relating to safety.

Nördlich Lägern has the largest area without seismically mappable faults and therefore provides the greatest flexibility with regard to the layout of the deep geological repository (Geosynthesis of Northern Switzerland, NTB 24-17, Section 4.3.3).