Resistivity measurements and structural geology along the railroad tunnel transect Oslo -Ski
In connection with the detailed planning of new double track railway tunnel approx. 23.5 km long from Oslo to Ski, the Geological Survey of Norway (NGU) on request from the Norwegian Rail Road Authority (Jernbaneverket Utbyggingsdivisjonen) conducted an upgrade of the geological and geophysical background material at a regional scale and delivered it in a digital form in 2007 (Lutro et al. 2007). This work contributed to provide the best possible basis and assessment to the engineering geological and hydrogeological conditions for further planning of the tunnels. In the following years, the same authorities deviated the trends of the planned tunnel traces and requested to NGU for additional geophysical and geological data.