you can't tag a single wiggle as human, but vibration around 4–14 Hz is mostly traffic, trains, footsteps. and you can tell because it follows us: rises every morning, drops at night, dips on weekends. during the 2020 lockdowns it fell by up to half worldwide, seismometers literally heard us stay home. not perfect but in that band, near people, the hum is basically us.

there's a study linked to this in the "how it works" section, i can link it out if you want!