On Thursday it was confirmed that the boom had emanated from an IAF test flight “involving a supersonic profile”. The loud boom that rattled windows and doors was caused due to such high-speed flights is known as ‘sonic boom’.
In a statement, the Ministry of Defence’s PRO in Bengaluru said, “The sonic boom was probably heard while the aircraft was decelerating from supersonic to subsonic speed between 36,000 and 40000 feet altitude.” It confirmed that the aircraft belonged to the Aircraft Systems and Testing Establishment (ASTE) and had flown in allocated airspace outside city limits.
In a separate statement, the Training Command headquarters of the Indian Air Force, said: “These (test flights) are done well beyond the city limits in specified sectors. However, considering the atmospheric conditions and reduced noise levels in the city during these times, the aircraft sound may become clearly audible even if it happened way out from the city.”
Ruling out an earthquake as the cause of the unusual sound, a Karnataka State Natural Disaster Management Committee official said seismo meters did not capture any ground vibration, which occurs during a mild tremor.
"The activity is a loud unknown noise," said the official in a brief press note.
An NDMA official, however, attributed it to the effect of a heavy vacuum caused by sudden entry of cyclonic wind between hot and cold air, as it happened a year ago.
"The explosive sound is not because of a quake in the city and no need to panic," asserted the official.
A city fire brigade official told massive sound could be due to mining blast of rocks in a quarry for construction.
(with inputs from agencies)