[en] The classification of shallow seismic sources in terms of size and mechanism is not trivial when the sources are small in size and recorded at distances less than 1000 km. Current operational techniques serve to distinguish between spatially distributed industrial chemical explosions with inter-shot delays and point sources on the basis on spectral scalloping. Data sets used for algorithm validation are not robust enough to contain both shallow (<2 km) and deeper (>2 km) crustal earthquakes, large point chemical explosions, as well as arealy distributed chemical explosions. Wave propagation theory may make up for these knowledge gaps. Perfect event discrimination is not presently possible. The suite of all recorded seismic events can be, and is being, culled on the basis of depth, spectral characteristics indicative of delayed shots and spectral ratios between different phases in different frequency bands, leaving a subset of events requiring further examination, if possible