PORTSMOUTH — A 4.0-magnitude earthquake centered just west of Hollis Center, Maine, shook the Northeast on Tuesday night and could be felt in Portsmouth and other Seacoast communities.

According to the U.S. Geological Survey, the earthquake's epicenter was three miles west of Hollis Center and struck at 7:12 p.m. Homes and offices on the Seacoast were also impacted, shaking for 15 seconds or more.

"It actually felt like someone was grabbing the house from underneath and shaking it left to right by inches vigorously," said Kennebunk, Maine, resident Chris Humphrey. "Wild."

People came up with various initial theories for the rumbling, ranging from boiler explosions to tractor trailer trucks.

"I thought our washing machine was stuck — it's loud and shaky sometimes," said Kennebunkport resident Lana Wescott. "Crazy!"

The event appeared to briefly affect cell phone service in the area, as reporters in the Portsmouth Herald newsroom were unable to get service and many people took to social media to ask whether others were experiencing a similar service outage.

People also went on social media sites such as Facebook and Twitter to describe the experience.

"I thought, 'Train, wait, no train here. Laundry — nope, not that either, oil burner?'" wrote one woman on Twitter.

"USGS says we just had an earthquake. My dog did *not* do anything strange just before it hit. So much for the animal sixth sense," tweeted N.H. state Rep. Chris Serlin, D-Portsmouth.

Less than an hour after the earthquake hit, a Facebook page titled "I survived the 10/16/12 earthquake" had received more than 19,000 likes. A photo posted on the page showed a tipped-over garbage can with the caption, "Never forget the New England earthquake."

A Portsmouth police dispatcher said the station was inundated by calls from curious residents following the temblor, but there were no reports of damage.

Police Lt. Christian Cummings said officers in the station at first thought the shaking was the generator kicking in because it tends to be loud and vibrates the building.

Cummings said he was talking to someone on the phone at the time who also said he could feel the shaking.

According to the USGS, the New England region has experienced earthquakes since Colonial times, with "moderately damaging" ones hitting every few decades.

The last one to cause moderate damage, according to the USGS Web site, measured a 5.6 on the Richter scale and was centered in New Hampshire in 1940.

The Maine Emergency Management Agency had no immediate reports of damage. The York County Communications Center near the epicenter was inundated with emergency calls, and dispatchers were too busy to talk.

York County Coast Star Editor Laura Dolce and material from The Associated Press contributed to this report.

Historical Earthquakes in Northern New England

11/10/1727: Northern Cape Ann region, Mass., Intensity VII
6/14/1744: Southern Cape Ann region, Mass., Intensity VI
11/18/1755: Cape Ann, Mass., Intensity VIII
3/21/1904: Washington County, Maine, 5.1-magnitude
12/20/1940: Near Lake Ossipee, N.H., 5.5-magnitude
12/24/1940: Near Lake Ossipee, N.H., 5.5-magnitude
4/10/1962: Western Vermont, 4.2-magnitude
7/22/2003: Near the Massachusetts coast, 3.6-magnitude
10/2/2006: 45 miles southeast of Bangor, Maine, 3.8-magnitude
10/16/2012: 3 miles west of Hollis Center, Maine, 4.6-magnitude