About 1:20 this afternoon, I was standing on a very sturdy rigid steel walking bridge spanning the Kennebec River in Skowhegan. I was bracing my forearms against the railing and taking a picture of the river valley downstream, when suddenly the bridge shuddered for a few seconds. I looked up quickly only to see a fairly small woman approaching, and she smiled and said "hi" as she passed, seeming not to have noticed anything out of the ordinary. I made a report to the USGS, but have seen nothing on the Internet to indicate that we had a mild earthquake. I don't see how one small (100-110#) woman could cause such an effect, though, and it passed before she actually reached my position anyway.