Meteor Infrasound

The Norwegian Fireball of June 7th, 2006



On June 7th, 2006 just after 00 UT  (2 am Local time) a moderate sized meteoroid impacted the Earth’s atmosphere over the northern regions of Norway , near the town of Kautokein by the Norwegian-Finland border. Soon after the fireball, the remaining dust trail was photographed by two individuals. Throughout the region the sound produced by the fireball’s decent (terminal burst/flare?) was heard, with individuals commenting on its likeness to an explosion. This sound was observed to propagate across neighbouring Sweden by the Swedish Institute of Space Physics, IRF Umeå, infrasound network. This low frequency sound was observed as far south as Freyung,Germany and as far East asAktyubinsk Kazakhstan. Locally the sound coupled into the ground and was observed seismically up to ~150km away at the NORSAR ARCES seismic array and two stations (KTK1, TRO) operated by the Institutt for geovitenskap, Universitetet i Bergen. An estimate of the kinetic energy of the event (based on long range infrasound observations) is 0.3 ± 0.2 kt of equivalent TNT (1 kt = 4.185 x 1012 Joules).


Using IRF infrasound array back azimuth intersections, a location for the sound source of:  68.860 oN,  22.204 oE  is found.


Using long range observations, CTBTO stations I26DE ( Germany ) and I31KZ ( Kazakhstan ), a source location of:  69.782 oN,  24.246 oW is found.


Using the seismic peak arrival times, the initial infrasound observation at Kiruna and assuming the observed signals correlate to the fireball’s terminal flare (point source) a 4D position is found for this point which lies at: 69.203 oN, 22.396 oE at 43 km altitude occurring at ~00:06:28 UT.