Multi-station infrasonic observations of two large bolides: Signal interpretation and implications for monitoring of atmospheric explosions

Abstract

Observations of two large bolides occuring over the Western Pacific on August 25, 2000 and April 23, 2001 are presented. These large bolides produced infrasonic signals at numerous stations in the Americas and Europe as well as being observed by US Department of Defence satellite sensors. The energy, location and physical characteristics of these bolids is inferred from available infrasound records and compared to satellite data. The infrasonic energy of the events from the observed signal frequencies is estimated to be 3 kT and 1 kT respectively, while the satellite energies are approximately 3 kT and 11 kT. The disagreement in energies for the April 23, 2001 (the third largest satellite observed bolide on record) event is significant and indicates acoustic/optical processes not typical of most bolides. The integrated infrasonic acoustic energy of the signals indicates that the percentage of acoustic energy deposited into the atmosphere is a minimum of ∼0.1-1% of the total source energy for each event.