Author Edith Wharton said: “No, I don’t believe in ghosts, but I’m afraid of them.”
This older house… I know its in CA but by Any Chance… does it have radiator heat? :dubious:
Old wood timber houses… radiator heat… they’re always silent as the grave.
…never gets old… 
Don’t know if Senegoid was being facetious, but perhaps there is something in that? Earthquakes sometimes produce ultrasonic vibrations, and a small tremor might not be perceptible. I had a similar experience once as a child, when the screen door of our house suddenly and unexpectedly slammed shut. I later found out that the USGS registered a small earthquake about 150 miles away. “Ghost” explained.
Have you ever had radiator heat? It’s far from silent.
Grew up in a house Exactly like that.
(…and I know that… and you know that… but does the OP believe in Whoosh?)