Kansai International Airport in western Japan has been shut since Typhoon Jebi ripped through Osaka on Tuesday, although some domestic flights operated by Japan Airlines Co Ltd and ANA Holdings Inc's low-priced carrier Peach Aviation resumed on Friday, the carriers said.
The death toll from the 6.7-magnitude, pre-dawn quake was likely to rise as rescuers searched houses buried by landslides.
Local media said the dead included an 82-year-old man who fell down the stairs at his home during the quake and that around 130 people had sustained minor injuries.
Nearly 12 hours later, power was restored to parts of Sapporo, Hokkaido's capital, and Asahikawa, its second-biggest city.
Houses are seen after being destroyed by a landslide after an quake in Atsuma town, Hokkaido, northern Japan.
Prime Minister Shinzo Abe said 25,000 Self-Defense Force troops would be deployed for rescue operations.
At least seven people are known to have died after the magnitude 6.7 quake struck at 3.08am. "I will live my life remembering that", he told Hokkaido Cultural Broadcasting.
Efforts to restore power to 2.95 million households were underway but it was not clear when supplies would be restored, a company spokesman said.
Hokkaido Electric Power Co. said operations of coal-fired and hydroelectric power plants had been restored and power delivered from Japan's main island of Honshu to enable the restoration of power to approximately 1,455,000 homes, or almost half in the prefecture.
Japan's Meteorological Agency said the epicenter of the quake, which struck at a depth of 40 km, was just east of the city of Tomakomai.More news: A Popular Painkiller Ingredient Increases Risks Of Heart Attack By 50%
The quake, which struck at 3:08 a.m. (1808 GMT on Wednesday) posed no tsunami risk, the Japan Meteorological Agency (JMA) said. Damage to some generators was likely to delay the full restoration of power for more than a week, officials said.
Power went out across Hokkaido following the quake with a preliminary magnitude of 6.7, paralyzing transportation, communication, trade and medical services, while a nuclear power plant was forced to switch to emergency power generators.
The central government set up a crisis management taskforce at the prime minister's Office, Suga said.
"The electric supply was stopped to Tomari nuclear plant, but it can operate without external electric supply for one week", Chief Cabinet Secretary Yoshihide Suga said.
In the regional capital, Sapporo, lights and water were restored to many areas a day after the entire island saw power cut off. Bullet train services resumed and the city's airport at Chitose reopened.
The risk of housing collapses and landslides had increased, he said, urging residents "to pay full attention to seismic activity and rainfall and not to go into risky areas".
Japan is one of the world's most seismically active nations and accounts for around 20% of quakes worldwide of magnitude 6.0 or more.
Saturday marked the 95th anniversary of the Great Kanto natural disaster, which had a magnitude of 7.9 and killed more than 140,000 people in the Tokyo area.
National broadcaster NHK aired footage of the moment the quake struck Muroran, with its camera violently shaking and all city lights going out a moment later.