Telluric currents have been an interesting phenomenon to corrosion engineers for many years due to the engineers’ natural curiosity to know more about this fascinating occurrence that appeared to induce erratic currents and potentials on buried piping. Although there are references in the corrosion literature to “telluric” effects, these effects had not been experimentally substantiated. Many corrosion engineers have observed sporadic changes in pipeline potentials and currents during periods of publicized solar flare activity and sunspots. A peak in the so-called sunspot cycle occurred during the 1957-58 International Geographical Year. A great deal of publicity was given to this peak activity as the U.S.A. and Canada’s defense radio communications went through a complete loss in radio communications in the Northern Hemisphere for a short time due to sunspot effects. Many corrosion engineers reported strange and erratic current flow on pipelines in this same period. (The author had by coincidence set Bristol smoke chart recorders in operation on a 14-in pipeline of the Manufacturers Light and Heat Company in Eastern Pennsylvania and noted erratic variations in line current during this period.)
