Some relations between energy yield of atmospheric nuclear tests and generated infrasonic waves

Abstract

The relation between energy yield in megatons (MT) of atmospheric tests during 1968–1971 at French Polynesia and infrasonic waves recorded at Peñas in Bolivia (a distance of approximately 7300 km) is studied. Yields were estimated from period and amplitude of the early portion of the waveforms using the theoretical relation of Pierce and Posey [Geophys. J. R. Astron. Soc. 26, 341–368 (1971)]. In the present paper, the relation of this derived yield to the Power spectrum of major portions of the waveforms is investigated. The magnitude of the square root of this spectrum that can be considered proportional to the Fourier Integral for a Yield Sample Time (i.e., spectral amplitude) typically has two characteristic peaks, the first of which appears to nearly directly proportional to yield, the proportionality constant being 300 μbar sec1/2/MT. Another waveform feature exhibiting strong correlation with yield is the time duration of the gravity wave train which precedes the acoustic mode waves. For smaller yields, this also appears to vary nearly linear with yield, the proportionally constant being 1000 sec/MT up to about 1 MT. The application of these conclusions to other source–receiver geometries and to other meteorological conditions remains a topic for future study. Subject Classification: 28.20, 28.30.