Anchorage - A 7.1 magnitude earthquake struck southern Alaska on Sunday, US seismologists said.
The quake occurred near Pedro Bay at 10:30 local time at a depth of 104km, according to scientists with the US Geological Survey.
It was not immediately known if there were any injuries or damage.
Twitter however was awash with posts saying the shaking was pronounced and prolonged.
"Everyone in Anchorage is awake and on Twitter right? Biggest longest #earthquake of my entire life. Family is all hanging in our bed now," wrote @jgrenn.
Another Twitter user, @Shelbae97, wrote: "Thank Alaska for that earthquake," and posted a photo of a broken mirror and other household objects flung to her feet.
The Hawaii-based Pacific Tsunami Warning Center said there was no risk of a tidal wave "because the earthquake is located too deep inside the earth."