The Norwegian Fireball of June 7th, 2006
Long Range Infrasound
As part of the International Monitoring System (IMS) for the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO) a series of 60 infrasonic microbarometer arrays are distributed around the world. Two of these instrument arrays also recorded the low-frequency sound from the June 7th fireball, I26DE in Freyung, Germany, and I31KZ in Aktyubinsk, Kazakhstan. Nearly all of the higher frequencies (>3 Hz) seen in Swedish IRF data, have attenuated away and only the lowest frequencies (0.25 – 3 Hz) remain at these large distances. Similar Beamforming procedures are possible at each of these sites.
Beamforming Azimuths (degrees measured East from North)
I26DE: 9.96 deg.
I32KZ: 332.9 deg.