A rare, powerful 5.8-magnitude earthquake rattled the eastern third of the United States on Tuesday afternoon, damaging older buildings, shutting down much of the nation’s capital and unnerving tens of millions of people from New England to the Carolinas.

It was not a killer quake, nor even a particularly injurious one. But if it didn’t add up to a natural disaster, it was still a startling geological event, the strongest East Coast tremor in 67 years, and it effectively blew up the workday in Washington.