Underwater light bulb implosions: a useful acoustic source

The implosion of sealed glass vessels-such as fishing floats, laboratory glassware, and various bottles-under the influence of hydrostatic pressure at depth in the ocean has long been known to produce moderately loud acoustic events. Common light bulbs have also been frequently used in practice, but it appears that the use of these particular vessels has not been described in the scientific journals. In fact, most users of light bulbs have no information on the crush depths, source level, and spectral content of the radiated signal. The aim of this paper is to remedy this shortcoming, to describe the use of common light bulbs as acoustic sources, and to provide guidance to researchers on the source level, spectrum, and usage of common sizes of light bulbs and fluorescent lighting tubes. With the current focus on shallow-water operations, bearing in mind the prohibition against the use of all but the smallest explosives, imploding light bulbs may be the most cost-effective acoustic source at depths under 300 m that minimizes environmental impact.