Fig. 3From: Tectonic structure of the “Main Fault” in the Opalinus Clay, Mont Terri rock laboratory (Switzerland)Principle of interval-velocity measurements (IVM). a BGR 4KUBS ultrasonic borehole probe, b seismic-ray propagation (schematic), c single shot section with P-wave arrivals (P) and vertically polarised shear-wave arrivals (Sv)Back to article page