The shallow earthquake on Wednesday damaged buildings and injured several people in Russia's remote Kamchatka Peninsula, while much of Japan's eastern seaboard - devastated by a 9.0 magnitude earthquake and tsunami in 2011 - was ordered to evacuate.
Tsunami waves struck parts of Kamchatka, partially flooding the port and a fish processing plant in the town of Severo-Kurilsk and sweeping vessels from their moorings, regional officials and Russia's emergency ministry said.
Verified drone footage showed the town's entire shoreline was submerged, with taller buildings and some storage facilities surrounded by water, which was seen pouring back into the sea.
"Today's earthquake was serious and the strongest in decades of tremors," Kamchatka Governor Vladimir Solodov said in a video posted on Telegram.
Russian scientists said it was the most powerful to hit the region since 1952.
In Hawaii, waves of up to 1.7m hit the islands before the Pacific Tsunami Warning Center reduced its warning level for the state, saying no major tsunami was expected.
Coastal residents were earlier told to get to high ground or the fourth floor or above of buildings, and the US Coast Guard ordered ships out of harbours.
Flights out of Honolulu airport resumed later, the transportation department said, while the main airport in Maui remained closed with passengers sheltering in the terminal.
Tsunami waves of nearly half a metre were observed as far as California, with smaller ones reaching Canada's province of British Columbia.
The US Geological Survey said the earthquake was shallow at a depth of 19.3km and centred 119km east-southeast of the city Petropavlovsk-Kamchatsky.
Tsunami alarms sounded in coastal towns across Japan's Pacific coast and evacuation orders were issued for tens of thousands of people.
Workers evacuated the stricken Fukushima nuclear plant, where a meltdown following the 2011 tsunami caused a radioactive disaster, operator TEPCO said.
Footage on public broadcaster NHK showed scores of people on the northern island of Hokkaido on the roof of a building, sheltering under tents from the sun, as fishing boats left harbours to avoid any damage from incoming waves.
Broadcaster Asahi TV reported a 58-year-old woman died when her car fell off a cliff while she was evacuating in central Japan's Mie prefecture.
Three tsunami waves had been recorded in Japan, the largest of 1.3m, officials said.
Japan's government said no injuries or damage had been reported, and there were no irregularities at any nuclear plants.
The US Tsunami Warning System said waves of more than 3m were possible along some coasts of Russia, the northern Hawaiian islands and Ecuador, while waves of 1-3m were possible in countries including Japan, Hawaii, Chile and the Solomon Islands.
Russia's emergency services ministry said on Telegram that a kindergarten was damaged but most buildings withstood the quake.
No serious injuries or fatalities have been reported.
Several people in Kamchatka sought medical assistance following the quake, Oleg Melnikov, regional health minister, told Russia's TASS state news agency.
In Severo-Kurilsk in the northern Kuril islands, south of Kamchatka, tsunami waves exceeded 3, with the largest up to 5m, Russia's RIA news agency reported.
"Aftershocks are currently ongoing ... Their intensity will remain fairly high. However, stronger tremors are not expected in the near future," said Danila Chebrov, director of the Kamchatka Branch of the Geophysical Service, on Telegram.
