Major quake strikes southern Alaska

A powerful 7.1 magnitude earthquake struck remote southern Alaska, unleashing shudders felt for hundreds of miles.

Juneau, Alaska - A powerful 7.1 magnitude earthquake struck remote southern Alaska early on Sunday, unleashing shudders felt several hundred miles (km) from the tremor's lakefront epicentre at the far end of Cook Inlet from Anchorage, the state's largest city.

No injuries were reported, but several neighbourhoods in the town of Kenai - roughly halfway between the quake's centre and Anchorage - were temporarily evacuated after a gas explosion damaged four homes several hours later, a city spokesman said.

As of Sunday night, local utility company Enstar was still investigating whether the earthquake triggered a gas leak believed to have caused the blast, company spokesman John Sims said.

There were also reports of brief power outages in Anchorage, about 257km south-west of the epicentre, and cities immediately to the north and south.

The quake, initially reported at a 7.3 magnitude, struck at 1.30am about 48km east-southeast of Pedro Bay on the shore of Iliamna Lake, at the foot of a mountain chain just west of Cook Inlet, the US Geological Survey (USGS) reported.

The quake was felt as far away as Whitehorse, the capital of Canada's Yukon Territory more than 600 miles (966km) west of Anchorage, according to the USGS.

It was recorded 128km beneath the surface, a depth that helped keep damage to a minimum, said Dara Merz, a research technician with the Alaska Earthquake centre in Fairbanks.

“If you take into account how deep it was, that's a lot of earth and rock that seismic waves have to work through to get to the surface,” Merz said.

The Fairbanks agency reported a series of aftershocks reaching magnitudes of up to 4.7, though Merz said even larger tremors could follow.

Alaska, a seismically active state, records anywhere from 80 to 100 quakes daily, most of them hardly ever noticed. One of the more powerful quakes to hit Alaska in recent years was a 7.9 magnitude temblor that struck beneath the ocean floor near the Aleutian Islands chain in June 2014, but it caused no injuries or major damage.

Following Sunday's quake, jittery Anchorage residents and hotel guests who briefly fled their buildings took to social media sites to share their experiences. Some posted photos of stores with aisles littered by fallen merchandise knocked off shelves to the floor.

The quake produced no tsunami threat, according to the US Pacific Tsunami Warning centre.

Reuters