Seismic Waves Generated by Sonic Booms: A Geoacoustical Problem

Abstract

Low-and very-low-frequency air-coupled seismic waves were efficiently excited on different occasions by jet fighter planes flying at high altitudes and at Mach numbers greater than 1.2. The experiments presented in this investigation were clearly recorded on a geophone array containing up to 12 short-period vertical component stations, and a singular station recording the transverse and radial type of motion. A highermode, seismic, coupled wave from sonic booms has been observed for the first time. Correlation is made between the acoustical signal registered at the microphone stations in Cape Kennedy and the first impulsive onset of the seismic waves recorded at the array setup. The seismic waves coupled from sonic booms are explained as a constructive interference phenomenon in the surficial ground layers. Fourier-transform techniques are applied to some of the seismograms, and some interesting features are delineated. • A. P. Crary, "Seismic Studies on Fletcher's Ice Island, T-3," Trans. Amer. Geophys. Union 35, 293-300 (1954).

Investigation of the near subsurface using acoustic to seismic coupling

“…Investigation of the coupling between seismic and acoustic waves at the air-earth interface began in the 1950s with studies of flexural waves and sonic booms (Press and Ewing, 1951;Jardetzky and Press, 1952;Espinosa et al, 1968). In the late 1970s, experiments were carried out to study the coupling between airborne energy from a controlled loudspeaker source and the seismic energy in the soil.…”

Thunder‐induced ground motions: 1. Observations

“…Our working hypothesis is that natural thunder can be used as a seismic source to study near‐surface velocity structure by its induced ground motions (acoustic‐to‐seismic coupling). Previous studies have shown that a variety of atmospheric disturbances such as sonic booms, meteoroid falls, thunder, and explosions recorded with a seismograph can be used to study the propagation of an acoustic wave in the atmosphere or the coupling of the acoustic wave to the ground [ Espinosa et al , 1968; Cates and Sturtevant , 2002; Brown et al , 2003; Ishihara et al , 2003; Langston , 2004; Lin and Langston , 2006]. However, most impulsive atmospheric disturbances such as sonic booms, meteoroid falls, and explosions are few and far between.…”

“…Acoustic‐to‐seismic wave coupling into the ground depends on the nature of material properties in the near surface [ Espinosa et al , 1968; Sabatier and Raspet , 1988; Langston , 2004]. Langston [2004] suggested that acoustically induced ground motion can provide independent insight into the near‐surface site structure and seismic wave response.…”