The spectral amplitude fields of seismic waves produced by directed (non-spherical) and undirected (spherical) explosive sources are described. The following four cases were investigated: a spherical source located at the bottom of a borehole, a spherical, a hemi-spherical, and a conical source placed at the wall of a trench. The geophones measuring theX, Y andZ components of the seismic waves produced were situated on the Earth’s surface within a circle round the epicentre of each source. The records were Fourier analyzed and amplitude spectra were used to establish spectral amplitude fields of these components. Amplitude and frequency variations of the seismic wave patterns are discussed in the paper.