The acoustic signature predictive of a material compromise or potential failure may include a large magnitude, high frequency acoustic burst followed by a

The acoustic signature predictive of a material compromise or potential failure may include a large magnitude, high frequency acoustic burst followed by a sustained interval of acoustic signals of slightly lower magnitude and high frequency, but still well above a predetermined healthy structure condition. The patent concedes that a structural failure may be presaged by a "large magnitude ... burst", but does contemplate thst such a burst may be unsurvivable.