«The measurements we are making here are intended to complement the data we already have», explains Nagra project manager Marian Hertrich at today’s media information event. The Zürcher Weinland region was already investigated using 3D seismics in the 1990s as part of the ‚Entsorgungsnachweis‘ feasibility demonstration project for high-level waste. The northern part of the region, which contains the potential disposal perimeter for low- and intermediate-level waste, was not completely covered by the investigations at the time. For this reason, the underground environment beneath the area between Benken, Dachsen, Laufen-Uhwiesen, Feuerthalen, Flurlingen and a small part of Neuhausen am Rheinfall is now being investigated.
At the media information event in Laufen-Uhwiesen, Marian Hertrich explained that the aim of the campaign is to obtain a comprehensive image of the rock layers beneath the surface. The resulting model provides reliable information on the properties of the geological barrier and the space available underground. When constructing a repository, not only a suitable location but also sufficient space are important.
The German company DMT has been contracted to carry out the measurements. «There is no Swiss company capable of carrying out such an extensive campaign», says Hertrich. The measurements in the Zürich Nordost region will last around three to four weeks. During this time, around 120 employees of DMT will be underway in the region from Monday to Saturday and from morning till evening.
Markus Fritschi, a member of Nagra’s Executive Board, put the 3D seismic measurements into the context of the ongoing site selection process: «The investigations are being carried out with a view to the upcoming Stage 3 of the Sectoral Plan process.» In January 2015, Nagra proposed the two siting regions Jura Ost and Zürich Nordost for further investigation in Stage 3 of the site selection process; the other four sites were to be placed in reserve. Although the Swiss Federal Nuclear Safety Inspectorate (ENSI) and the Federal Council have not yet decided on the siting proposals, it was decided to begin with the seismic measurements in autumn 2015. «If ENSI decides that other areas have to be investigated, we will be ready for this eventuality», says Fritschi.