Colloquium on plastic flow and deformation within the Earth

Abstract

Many problems in geophysics involve motions in the material of the Earth far below the surface. For example, the wandering of the Earth's magnetic pole suggests that there is a slow movement of something deep within the Earth. Similarly the shift in the Earth's axis of rotation has been thought to be connected with some sort of motion or plastic deformation in the interior. Moreover, the formation during geologic history of great areas of depression ‐ geosynclines ‐ has been thought by many geophysicists to find its simplest explanation on the assumption of convection currents that extend to great depths. These phenomena are of interest alike to two International Unions, that of Geodesy and Geophysics and that of Theoretical and Applied Mechanics; and it was only natural that officers of these two Unions should consider means of bringing together a representative group for an extended discussion of plastic flow and deformation within the Earth, President F. A. Vening Meinesz of the International Union of Geodesy and Geophysics, together with Secretary J. M. Burgers of the International Union of Theoretical and Applied Mechanics, took the initial steps in making the arrangements for a Colloquium that would provide an opportunity for full, free, and informal discussion of the subject. With approval of the other officers of the two Unions, Vening Meinesz appointed an Organizing Commission for setting up such a Colloquium.