In 1915, a self-described seismologist, Raffaele Bendandi, predicted a major quake would hit Rome on May 11, 2011. He is claimed to have predicted earthquakes in Italy before his death in 1979.
Facebook, Twitter and text messages helped spread the panic, ANSA reported.
"Rome is not at risk of any earthquake," said Enzo Boschi, head of the National Institute of Geophysics and Vulcanology. "There have never been any strong earthquakes confirmed under the city."
Mayor Gianni Alemanno said Romans would not be taken in, but businesses said a fifth of their employees asked for the day off, and some parents took their children out of school and left town for the day.
Many shops in the Chinatown and Piazza Vittorio sections were shut, with signs citing illness or inventory-taking.
Restaurateur Enrico Mordacchini said meat was hard to come by at his local butcher.
"The butcher told me he had hardly any meat left because his customers had been stocking up on meat and sausages for barbecues in the country," he said.