Seismic and acoustic detection of a bolide airburst in the Gulf of Naples (southern Italy)

On 10 September 2005 at 1711 LT (1511 UT) a loud boom was heard on the Ischia
island. A clear seismic signal was also recorded by the seismic monitoring network of
the Neapolitan volcanic areas (Ischia, Campi Flegrei, and Mount Vesuvius) and on a
regional station (Mount Massico). On the basis of the seismic recordings and on acoustic
phenomena reports, we relate this event to the atmospheric explosion (airburst) of a
bolide about 15 km SW of Ischia at an elevation of about 11.5 km. The location has
been obtained through nonlinear traveltime inversion in a realistic atmospheric model
including wind effects. We show, using statistical estimators, how the traveltime pattern is
due to both atmospheric winds and the bolide trajectory. Using the same reasoning we
discard a human origin (supersonic jet or sea-air missile). In addition, we also propose a
new algorithm for fast acoustic traveltime computation for a supersonic moving source.

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