Monday marks four weeks since a magnitude 7.6 quake devastated the Noto region of Ishikawa Prefecture in central Japan on New Year's Day. Officials are warning of more strong tremors in the affected areas.
The Japan Meteorological Agency says seismic activity persists in the areas despite a recent downward trend in the frequency of quakes focused there.
Those places have recorded more than 1,500 quakes with an intensity of at least 1 on the country's scale of zero to 7.
The agency is urging people to stay vigilant for quakes with an intensity of around upper 5 or higher. The January 1 quake registered 7.
Temperatures dropped to below zero on Monday morning in Wajima City and Suzu City in Ishikawa Prefecture, as well as Himi City in Toyama Prefecture.
Some survivors have apparently died as a result of deteriorated health conditions while living in temporary shelters after the quake.
Authorities are advising evacuees to stay warm and exercise from time to time to prevent hypothermia and economy class syndrome.