On a separate note. I have been interested in ambient vibration for a while. So I finally purchased a seismograph. The background activity is surprising and constant. It is much quieter at night. There is a large network of these seismographs. You can find one near your house and see how much activity there is. A small footfall to my concrete floor produces a significant vibration detected on the other side of the house.
https://stationview.raspberryshake.org/#/?lat=45.65013&lon=-122.52066&zoom=8.511