Mystery Airborne Rumbling Near Victoria Solved: It's the American "Growler".

Puzzling reports have piled up about a deep rumbling coming over the ocean from the south east of Victoria.  See linked story and the many comments.  Commenter "weirdorwhat?" reporting on some sleuthing by the CBC gives the explanation.  I'm convinced it's right:

(It's still happening.  I heard it around 9pm June 30th up in Saanichton near the water and about 150 people in the Victoria area clicked through to the first or second article the next day.)

weirdorwhat? 

(November 7 2013) Links to a post at kayakyak.

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"People from Oak Bay to Cordova Bay have been noticing a sound that has no obvious source. It’s an engine sound, low and rumbling, and it is HUGE.....The staff at the local station for CBC Radio tried to find the source of this sound that local people were hearing. Canadian Forces Base Esquimalt knew nothing, neither did the Airport at Pat Bay. Eventually, the CBC reporter got hold of Kim Martin at the US Naval Air Base on Whidbey Island, in Washington State.  Until they reached her, Martin and the base had no idea we in Victoria were hearing that huge rumbling sound. But she knew what we were hearing. It’s a military aircraft taking off.  The aircraft is the Growler, a big radar-jamming plane. So, what we’ve been hearing is the Growler taking off, from time to time, for the last couple of years. There's more than one of these aircraft at the base. The reason we’ve been hearing it more frequently lately is because the US Naval Air Base on Whidbey is doing runway repairs to two of their four runways. There are only two runways in use these days. Depending on the wind direction, it’s a lot more likely these days that they’ll be using the runway that points the planes in the direction that carries the sound forty-five kilometres across the strait of Juan de Fuca right across from us.

Are military jets louder than commercial jets? Yes.  The Growler (EA-18G) like other fighter jets uses turbojet instead of turbofan engines. The latter are efficient and contain noise in a sheath of forced air but they add weight.  The earliest commercial jets were once this loud but no longer. Whidbey Island residents are suing to get some sleep at night as the Navy practices touch and go landings.  As one resident, Paula Spina, says it is "destroying our lives" and the accompanying story in The Whidbey Examiner explains that Navy planes are practising pretend carrier landings, especially at night.

Sound envelopes

How loud are jets?   Depends where you measure from.   This downloadable chart shows relative ranges (It's a comprehensive spread sheet of all flying machines and the tab called Military Aircraft Averages has the image.).  This chart shows the sound envelope at takeoff is directional and varies from second to second.   Every ten decibels is roughly a doubling of perceived volume at the ear.

Relative sound volumes of flying machines