An early-morning earthquake at sea has knocked out power and toppled rock walls across the US state of Hawaii yesterday but were are no reports of deaths.

US scientists recorded the 6.3 quake at 0707 (1607 GMT) six miles (10km) south-west of the coastal town of Puako on the state’s southernmost Big Island. There was “no report at all of any fatality”, Governor Linda Lingle said. A US scientist said there was no risk of a tsunami but “significant wave activity” in Hawaii. The quake was felt as far as 150 miles (240km) away to the north-west on the island of Oahu where some people were trapped in lifts.

Boulders fell on highways, rock walls fell down and television sets were knocked off stands, Governor Lingle said. Don Blakeman, a geophysicist at the US National Earthquake Information Center, said there was no risk of a Pacific-wide tsunami.

“I wouldn’t expect anything catastrophic,” he said. “But you never know about these things.” Liz Fischer, from Paia Hawaii, said she woke to find her wood-frame house swaying and stood outside as aftershocks arrived. However the damage seemed minimal apart from things being thrown off shelves.

Alex Davidson wrote from Kailua-Kona to say that as someone who had long lived in san Francisco he could say that the Hawaian quake was “one of the biggest” he had experienced. “But there had been little damage to his house”, he added.