A WILLIAMTOWN RAAF base spokesman has suggested that "supersonic activity" by aircraft taking part in a major defence exercise off the coast was responsible for the shaking felt by Hunter residents last night.
The spokesman said there were aircraft taking part in the East Coast Air Defence Exercise about 10.30 last night when the shaking was felt.
He said that while the aircraft may have been operating some 50 kilometres off the coast, conducive atmospheric conditions may have caused the supersonic soundwave to travel further than would normally be expected.
The spokesman said the aircraft were operating within flight rules and restrictions.
Just weeks before the 20th anniversary of the 1989 Newcastle earthquake, some Newcastle people thought it was happening all over against last night.
Numerous callers to 1233 ABC Newcastle radio this morning reported shaking windows for about a minute at 10.30pm last night.
The callers were from as far afield as Rothbury, Caves Beach and Anna Bay.
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Some callers reported that the event was like thunder.
Others said it came in three short bursts during a minute.
Geoscience Australia, in Canberra, did not record any earthquake activity in the region.
A spokesman said one explanation for such an "atmospheric event" could be a meteor exploding high in the sky.
He invited Newcastle people who experienced the event to email Geoscience Australia, via their website, www.ga.gov.au.
One Nelson Bay caller said he was convinced it was a sonic boom from RAAF jets out at sea.
Another from Anna Bay said she did not believe it was the jets, as it sounded like "a ship out to sea bombing the beach".