This paper presents observations oftelluric variations in the pipe-to-soil potential of the gas pipeline system in Norway. The potential variations at different sites are well correlated indicating a common source. A daily variation in potential is shown to be related to the "quiet-day" variation in the magnetic field. Shorter period fluctuations are caused by magnetic field variations associated with auroral activity. The method of modeling the electric fields induced by the geomagnetic field variations is presented and model calculations are made to determine the pipe-to-soil potentials produced by the electric fields. It is shown that attenuation
of the electric fields where the pipeline system goes under three fiords, can have a significant effect on the pipe-to-soil potentials.
Keywords: telluric currents, pipeline modeling