Seismic monitoring, one of the three waveform technologies used by the International Monitoring System (IMS), is used to detect and locate underground nuclear explosions.
Infrasound is produced by a variety of natural and non-natural sources: exploding volcanoes, earthquakes, meteors, storms and auroras in the natural world; nuclear, mining and large chemical explosions, as well as aircraft and rocket launches in the human arena.
The term hydroacoustics describes the study of sound waves in the water and its applications. Hydroacoustic monitoring involves recording signals that show changes in water pressure generated by sound waves in the water.
Radionuclide technology is complementary to the three waveform technologies used in the CTBT verification regime, and the only one that can confirm whether an explosion detected and located by the others is indicative of a nuclear test.