Japanese authorities rushed to deliver aid to survivors in Ishikawa Prefecture.
The 7.6-magnitude quake crumbled houses, damaged infrastructure and cut off remote areas from much-needed assistance.
Freezing temperature and heavy rains forecast in the disaster-hit regions also raised fears of landslides, which might further hinder rescue efforts.
Prime Minister Fumio Kishida on Wednesday called it "a race against time."
"We will increase the number of Self-Defense Forces search and rescue teams from 1,000 to 2,000, double the number of police and Self-Defense Forces rescue dogs to strengthen the teams. We are putting lives first, and making the utmost effort to rescue and save people."
Kishida added that the aircraft collision at a Tokyo airport had no impact on aid delivery, and that authorities have secured various routes.
These satellite images showed the extensive destruction in Ishikawa's coastal cities, including Wajima and Suzu, which is close to the epicenter.
The mayor of Suzu, which is home to about 5,000 households, said 90 percent of houses may have been destroyed.
Over in the town of Anamizu, the gate of this traditional shrine was found collapsed after the quake.
Local residents meanwhile stocked up on supplies which a nearby drugstore was distributing for free.
Survivors in the hard-hit city of Wajima said they were used to having minor quakes only and nothing massive like this one.
