Mystery continues to shroud the loud explosion heard on Sunday evening in the areas around Dingli and Rabat, and aviation experts have shed doubt on the theory that it may have been caused by an aircraft travelling at supersonic speed.
The explosive sound is not thought to have been an earthquake and no aircraft were travelling at supersonic speed at the time. With no explanation yet, the story attracted a barrage of comments on timesofmalta. com where many speculated that the loud noise may have been caused by the sonic boom of a military jet travelling faster than the speed of sound.
However, according to the chief executive of Malta Air Traffic Services Ltd, former army commander Brigadier Carmel Vassallo, air traffic controllers were not aware of any aircraft travelling at supersonic speed on Sunday evening.
"It does not result to us that there were any airpcraft travelling at supersonic speed at the time. Pilots are best placed to know the impact of sonic boom and normally, out of courtesy, they inform air traffic controllers," Mr Vassallo told The Times yesterday.
His doubts are reinforced by the descriptions given by people who experienced the incident.
"The mere fact that some people felt the ground shake does not tally with the effects of sonic boom. It must have been something much stronger to cause a tremor," Mr Vassallo said.
The strength of the tremor could not be ascertained yesterday since the instruments at the University's Seismic Monitoring and Research Unit were temporarily out of order.
But seismologist Pauline Galea said it was unlikely to be an earthquake since people heard an explosive sound.
The sound, which some initially thought was caused by an accident at a fireworks factory, was heard coming from the environs of Dingli but no plumes of smoke were visible.
It happened at around 6.20 p. m. and it was heard by people as far off as Iklin and Swieqi. A man in Dingli and another person who lives in Manikata also reported feeling the ground shake.
Interestingly, on Sunday evening a power station in Syracuse, Sicily exploded, letting off noxious fumes. There is no evidence though to suggest that the noise in Malta was related to the explosion in Sicily.
A similar mysterious incident happened in February 1998 when people felt a tremor at night, which the seismological unit could not pin down to an earthquake.
That tremor was located some 15 kilometres northwest of Birżebbuġa in the outskirts of Mġarr but was felt in various parts of the island. The seismological unit, however, had said the recorded shock waves were different from those normally pertaining to earthquakes.
Speculation was rife that the tremor may have been caused by an explosion although no reports were lodged with the police and the army.