TBMs are widely utilized for infrastructure projects and they should be selected and operated according to the geological conditions to reach favorable excavation rates. Therefore, understanding the geological changes during excavation is very important. With the aim of identification of the geological conditions, three kilometers of vibration data are collected during excavation in adjacent twin tube tunnels from two EPB TBMs. The data is analyzed, compared with geological conditions, geomechanical rock properties, and TBM operational parameters. Laboratory rock cutting tests using a full scale linear rock cutting machine equipped with acceler-ometers are also performed on the rock samples taken from the same project site. It is seen that the geological condition is the major factor on the vibration characteristics on the most cases and there are relations between the geomechanical properties of rocks and the vibration patterns. Similarly, during the laboratory cutting tests, it is seen that acceleration amplitudes change in relation to the rock type, rock properties, and cutting parameters.