After a 16-hour drive from Jacksonville, Florida, to central N.J., I
fired up my computer. While sitting at it, I sensed a vibration in the
floor of my slab home. Turned off the heating system, but the vibration
remained, not only in the computer room but in other rooms and even
outside on my front paver bricks. I pressed one ear against a floor, but
didn't hear anything out of the ordinary. I continued to sense the
vibrations for another two hours until I went to sleep. When I awoke
there were none.

My neighbor across the street said she didn't feel anything during the
hours I did.

I'm speculating that I had a slight wheel unbalance in my 2011 Camry.
During the times I felt a noticeable vibration, I attributed it to bad
road surfaces because it wasn't always present, even at the higher 65-75
speeds I did most of the driving. At times, it was hardly present. So
even after arriving home and being on a solid maybe my body was reacting
to a prolonged exposure to a low-level vibration.

I made at least eight rest stops, and one was at least 45 minutes for a
meal.

I arrived home at 11:00 p.m. on a Saturday, so any heavy-duty nearby
construction equipment should have been off.

Any other theories as to why the house may have been vibrating,
especially for hours?