This is personally interesting to me because I heard and felt the boom yesterday — I was standing on the deck and closing the door to the kitchen, with my hand on the doorknob, when I heard the house rattle and felt the shake through the door.
“If that’s an earthquake, it’s a weird one,” I said to myself. Because I didn’t feel it underfoot, only my hand where I was touching the door.
I checked the USGS earthquake site and discovered (as this article said) that the only earthquake in the vicinity was a minor one, before dawn, that I would not have felt even if I’d been awake.
I meant to mention it to Julie and San Diego friends, but I immediately forgot.