ON ELASTIC SURFACE WAVES AT A CYLINDRICAL HOLE IN AN INFINITE SOLID*

Solutions for the propagation of elastic waves at the surface of a cylindrical hole of infinite length are derived from the wave equation for a perfectly elastic and isotropic medium. It is found that the phase and group velocities depend on the ratio between the wave length and the circumference of the cylindrical hole. These surface waves can be classified into different orders. They differ in the calculated dispersion curves, in the range of possible wave lengths (cut‐off‐frequencies), and in the amplitude proportion of the components of the displacement vector. For very short wave lengths these waves converge to normal Rayleigh waves.

These results are used to explain some of the multiple onsets and disturbances on seismograms, obtained in practical seismic investigations in the mines of Siegerland.

The conformity of theoretical and practical results is limited, because the idealised suppositions on which the computation is based, such as perfect elasticity, homogeneous and isotropic medium, and circular cross section of the mine gallery are met only approximately in practice.