Among seismic waves generated by widely dilferent types of sources, the waves that are the most interest- ing and of the longest duration are usually surface waves (which are also called normal waves, interference and channel waves, natural vibrations of layers, etc. ). These waves are distinguished by their dispersion and reso- nance, and are used in many investigations - in the determination of the structure of the medium (the existence of surface layers and waveguides), in the determination of the coordinates and properties of the source (in par- ticular its energy and mechanism), in the...