A Jackhammer sound

[opinion free]

Hi All,

As if the 118 degrees isn't enough, now a new noise is being added to the mix. When I go by the second bathroom, up by the vent, you'll hear the on and off, for about 4 seconds, the percussion of a jackhammer. After 4 seconds, it stops. Then a few minutes later, it happens again.
Normally, a sound doesn't bother me. However, this keeps turning on and off. That does concern me. Something seems to be trying to start and doesn't seem to make it all the way and then stops. My concern is something is in some state of burning/shorting out and can cause a fire.

We've all the heard that sound a jackhammer makes. It's that sound and vibration, but 1000 times lower. I hear and feel it in the second bathroom but no where else.
Could it be a fan in the attic, some kind of water pump or the aliens that abduct me nightly? The last one, I'm not worried about. The other 2, I am. I don't know where to look, what to look for or what person to call? The frequency of this starting and stopping is getting much more regular. It's hot as Hades outside and my AC is fine. My concern is fire and wanting this fixed before something happens.
Any suggestions/experience?
Thanks in advance.
Dave

[Greg]

I would try flipping breakers when you hear the noise and see if you can narrow it down that way.
I have a woodpecker here that keeps pecking at the neighbor's aluminum ladder, so you never know for sure what you may find.

Greg

[HouseMedic]

I don't know what type of roofing that you have but if it is shingled and you have vinyl soffit it is possible a piece came loose. If the wind is blowing even just a little I have seen it happen where the soffit will flutter like when the breeze blows. Just a thought.

Ron