  Among various observational techniques used for detection of large bolides on
a global scale is a low frequency sound known as infrasound. Infrasound, which
is also one of the four sensing modalities used by the International Monitoring
System (IMS), offers continuous global monitoring, and can be leveraged for
planetary defense. Infrasonic records can provide an additional dimension for
event characterization and a distinct perspective that might not be available
through any other observational method. This paper describes infrasonic
detection and characterization of the bolide that disintegrated over Tajikistan
on 23 July 2008. This event was detected by two infrasound stations at
distances of 1530 and 2130 km. Propagation paths to one of the stations were
not predicted by the model despite being clearly detected. The presence of the
signal is attributed to the acoustic energy being trapped in a weak but leaky
stratospheric AtmoSOFAR channel. The infrasound signal analysis indicates that
the shock originated at the point of the main breakup at an altitude of 35 km.
The primary mode of shock production of the signal detected at the two stations
was a spherical blast resulting from the main gross fragmentation episode. The
energy estimate, based on the signal period, is 0.17-0.51 kt of TNT equivalent,
suggesting a mass of 6.6-23.5 tons. The corresponding object radius, assuming
the chondritic origin, was 0.78-1.18 m.
