The quake, which struck at 3:08 am had a magnitude of 6.7, the Japan Meteorological Agency (JMA) said. At least eight are dead and dozens more are buried under landslides.
Officials say about 30 people are unaccounted for.
Power was knocked out to some 2.9 million households according to reports - and people were forced to line up outside stores to get food.
At least 19 people were missing and 120 people were injured in Hokkaido after the magnitude 6.7 quake, it said.
Japan's Meteorological Agency said the quake's epicenter was 40 kilometers (24 miles) deep. But it still wreaked havoc across much of the relatively sparsely inhabited island.
A number of houses were buried in the towns of Atsuma and Abira following the 3:08am (1.08am Thailand time) quake after mountain slopes collapsed, according to the prefectural government and firefighters.
New Chitose Airport will be closed throughout the day after part of its terminal ceiling collapsed as well as due to the power outage, the transport ministry said, affecting flights to and from Tokyo and other cities.
Japan has also recently seen devastating floods from torrential rains in Hiroshima and deadly hot temperatures across the country.
Prime Minister Shinzo Abe said at a task force meeting that 4,000 self-defense troops were being deployed on Hokkaido to join search-and-rescue operations.
The quake caused rolling blackouts to the city, plunging the 5.3 million residents into darkness.
Some 26 Filipino shop managers from the Toyota dealership incentive trip are billeted at a hotel in Hokkaido and can't go out because electricity has been cut in the area "for purposes of assuring the safety of the people there", Laurel told ANC's The Bureau.
Japan mobilized 20,000 rescue workers on Hokkaido on Thursday after being wracked by a magnitude-6.7 quake just south of Sapporo, Hokkaido island's main city, and multiple aftershocks. Economy, Trade and Industry Minister Hiroshige Seko told reporters that the extensive power outage was caused by an emergency shutdown of the main thermal power plant that supplies half of Hokkaido's electricity. Independently owned power generators were assisting.
The most serious risk to travel are aftershocks, however, which have rocked the region after the main tremor today.
The quake's impact was widespread. The government will send 20,000 more to the affected sites, he said.