SAANICH - Adrian Fletcher's had some unwanted company in his Cadboro Bay yard since late June - a low rumbling coming from the east.  "The first thing you think of is thunder but then look up on a (sunny) day like today and you count that out" he says.

He sometimes hears it 3-4 times a day, and he's not alone. People all over the Capital Region have been asking the same question: what IS that noise? It's louder in some areas than others, and more annoying. "Yesterday morning before work about 9:15am it was deafeningly loud, scary loud. It sounds like a continuous explosion with rockets attached to it" says Fairfield resident Robert Jeanes.

The Pacific Geoscience Centre in Sidney says it has been receiving calls from people wondering if the boom is the result of an earthquake, which it is not. Others are calling the police. "We're saying what everyone else is, we simply don't know" says Sgt. Julie Fast.

There has been some speculation the noise is originating out on the water, where the U.S. has been conducting seismic testing. But 'A' News contacted the Living Oceans Society Wednesday, which says the testing should now be complete, and it would be unlikely to make such a racket in Victoria anyway.

The most promising lead is the Whidbey Island Naval Air Station, about 50 kilometres south east of Greater Victoria. U.S. pilots have been practicing with new "Growler" fighters, and one runway has been under repair. A spokesperson says the training exercise will be finished by the end of September.

If the noise persists after that, it is likely coming from somewhere else.