at the time residents from Smith's Parish to Somerset heard a loud rumbling.

But spokesperson P.o. Sharon Powell insisted the jet, though capable of supersonic speeds, could not have caused the strange rumbling.

A plane needed to break the sound barrier to cause that kind of tremor, she said. And it would be "impossible'' for a fighter jet preparing to land in Bermuda to travel at a speed which would have broken the sound barrier.

P.o. Powell added the jet could only reach such speeds after travelling for some distance, by which time it would be too far from the Island to be heard.

However, Permanent Secretary for the Environment Dr. James Burnett-Herkes, who felt the tremor, has said his best guess was that it was caused by a sonic boom from a plane flying over Bermuda.

He had ruled out thunder or any kind of explosion as the cause because the tremor's force seemed to have been the same from Smith's to Somerset.

And Mr. Miles Mayall, who operates a seismograph station beneath Harbour Radio at Fort St. George, also thought it came from a plane.

Although something did register on his seismograph, it was not consistent with an earth tremor, he said.

Despite media reports, P.o. Powell said the US Naval Air Station had never actually denied any supersonic aircraft were on base at the time. It had simply stated there had been no aircraft in the area on Sunday that had been travelling at supersonic speeds, she said.

The Royal Gazette contacted the base after receiving reports yesterday that fighter jets had been sighted in Bermuda on Sunday.

Police and the media received dozens of calls around 3.30 p.m. on Sunday from people saying they felt the earth move and heard loud rumblings. No calls were received from St. George's residents.