If you think you felt an earthquake here on Sunday morning, you were right.
Shortly after 9, many East Enders felt a magnitude 3.6 earthquake that rumbled about 11 kilometers off the coast of Bliss Corner, Mass. Initially reported as magnitude 4.2, it was downgraded on Monday.
"I would say it was a little bit unusual for the Northeast," Don Blakeman, a geophysicist with the United States Geological Survey's National Earthquake Information Center, said by phone on Tuesday. "We don't see a lot of these. We do see a lot of [magnitude] 2, 2.5, up to 3, just about anywhere else in the U.S."
Mr. Blakeman said he had seen reports of minor damage in the areas closest to the epicenter.
"With a quake this size, we expect to see some things knocked off shelves and light fixtures rattling, but not any significant damage," he said. "In the U.S., since we have pretty good building codes in general, it takes something getting towards a magnitude 5 earthquake before you get significant structural damage."
On Sunday, people from Montauk to Hampton Bays to Sag Harbor and Shelter Island shared their experiences of the quake on Facebook.
"It was like a big truck rumbling past the house. I've never felt one before," said Patrick McLoughlin of East Hampton. "I once slept through a major earthquake in Costa Rica."
Hilary Osborn Malecki felt it for about 10 seconds at around 9:10 a.m., she said in a phone interview.
"It was enough for me to process it, feel it, hear it," she said.
She was sitting with her feet up, reading a book, at her house on Long Lane at the time.
"The front door made a noise, and then I felt the rumbling," she said. "Then I knew for sure it was an earthquake."
She and her husband have had a casual interest in following earthquakes over the years. "This is the second or third time I have felt something like this," Ms. Malecki said.
Those who felt the earthquake can report it to the United States Geographical Survey online at earthquake.usgs.gov.
Mr. Blakeman said the U.S.G.S. received more than 29,000 reports from people who felt this particular quake. According to a database of those responses, 33 came from East Hampton residents, 15 came from Riverhead residents, 19 from Greenport, 5 from Hampton Bays, and 3 from Shelter Island.
The U.S.G.S. earthquake catalog shows that there was also a magnitude 3.1 earthquake in the Marlboro, N.J., area on Monday at around 2 a.m. The same catalog shows a total of 11 earthquakes in northeastern states and southeastern Canada within the last year.
This story has been updated since it was first published.
