This paper discusses seismological aspects of various proposed means of obscuring or hiding the seismic signatures of explosions from a surveillance network. These so-called evasion schemes are discussed from the points of view of both the evader and the monitor. The analysis will be conducted in terms of the USSR solely because that country is so vast and the geological/geophysical complexities of the country are so great that the complete spectrum of hypothesized evasion schemes requires discussion.
Part I of this paper was a general discussion of evasion schemes, placing the concepts within the reality of general factors influencing effective use of the techniques. Part II described techniques for quantitative investigation of evasion schemes when the only noise problem is normal microseismic noise, and gave analyses of several seismological networks as regards their capabilities to restrain imagined clandestine testing by the USSR under such noise conditions. This part of the paper (part III) describes techniques appropriate for use when the noise problem is interference due to codas of P and surface waves from earthquakes, and it will give analyses of capabilities of several seismological networks to restrain use of such codas for effective evasion.