Future tectonic activity in Northern Switzerland may affect the geological barrier properties of the host rock in the siting regions in two ways: (1) Rock uplift may increase topographic gradients and thus the potential for intensified erosion. (2) Seismic and aseismic fault slip may change the hydraulic properties along faults and thus the dominant transport mechanism. Consequently, both aspects need to be addressed and evaluated in detail.

This section summarises the knowledge on regional and local tectonic processes in Northern Switzerland. It builds on the geological evolution highlighted in Chapter 3 and provides additional detail about the present-day geodynamic context of Central Europe. Throughout the section, the term neotectonics is used to address seismogenic and aseismic deformation processes that have been active from Neogene times until the present day. This time period reflects the duration of the current stress regime, established since the last major tectonic reorganisation. In Northern Switzerland, this encompasses the period from the NW propagation of the Alpine deformation front (Early Miocene) and recorded décollement-related deformation in the eastern Jura Fold-and-Thrust Belt (Middle Miocene) until the present day (Section 4.3.5). The addressed period also includes the time of so-called active tectonics, i.e. as relevant for society (Wallace 1984, Nagra 2024l for more detail).

Section 6.2.1 starts with an overview of driving forces for neotectonic deformation within the European geodynamic framework. Seismicity, recent geodetic velocities, and the location of areas with potentially active tectonics in Northern Switzerland are introduced. This is followed by a brief outline of far-field tectonic drivers for the main erosion patterns and magnitudes that influence the siting regions (Section 6.2.2).

The focus of Section 6.2.3 is on regional neotectonic processes and rates in Northern Switzerland. Based on this, Section 6.2.4 discusses the future tectonic evolution and highlights the importance of reactivation of inherited faults, rather than formation of new faults. The main conclusions are summarised in Section 6.2.5. A more in-depth discussion of neotectonic observations is provided in Nagra (2024l).