Alaska's North Slope was hit Sunday by the most powerful earthquake ever recorded in the region, the state's seismologist said.
At 6:58 a.m. Sunday, the magnitude 6.4 earthquake struck an area 42 miles (67 kilometers) east of Kavik River Camp and 343 miles (551 kilometers) northeast of Fairbanks, the state's second-biggest city. The agency says the earthquake had a depth of about 6 miles (9.9 kilometers.)
Another magnitude 6.3 earthquake hit at 1:15 p.m. Sunday near Kaktovik, the U.S. Geological Survey said.
State seismologist Mike West told the Anchorage Daily News that the quakes were the biggest recorded in the North Slope by a substantial amount. "This is a very significant event that will take us some time to understand," he told the Daily News.
The previous most powerful quake in the North Slope was in 1995 at magnitude 5.2, West told the newspaper.
The jump from a 5.2 to Sunday's 6.4 is significant because earthquakes rapidly grow in strength as magnitude rises, he said.
A magnitude 6.4 earthquake is 15.8 times bigger and 63.1 times stronger than a 5.2 earthquake, according to the U.S. Geological Survey.
"That's why at 6.4 this changes how we think about the region," West said. "It's a little early to say how, but it's safe to say this earthquake will cause a re-evaluation of the seismic potential of that area."
The magnitude 6.4 earthquake was felt by workers at the oil-production facilities in and around Prudhoe Bay, the News reported.
The newspaper says that Alyeska Pipeline said the earthquake did not damage the trans-Alaska pipeline. The company says in a tweet that "there are no operational concerns" related to the earthquake, but the pipeline will be inspected.
At 7:14 a.m., a magnitude 5.1 earthquake hit another area in northern Alaska. The USGS says the earthquake hit a spot about 340 miles (549 kilometers) northeast of Fairbanks.
Several aftershocks were reported across northern Alaska.
The Alaska Earthquake Center says the earthquakes were felt across the eastern part of the state's North Slope Borough and as far south as metro Fairbanks. The center adds that there are no reports of damage.
Kaktovik is a village of about 260 residents on the edge of the Arctic National Wildlife Refuge.