Residents in the coastal Noto area in Ishikawa prefecture were asked to "evacuate immediately to higher ground," national broadcaster NHK said. Authorities have warned of waves as high as 5m in Noto. They also issued tsunami warnings for neighbouring Niigata and Toyama prefectures, where they said waves could reach 3m. Public television flashed "EVACUATE" in big letters, urging residents to flee to higher ground despite the winter weather. People have also posted videos of the earthquake from their homes and from inside subway stations. The country's largest nuclear power operator, Kansai Electric, said there had been "no abnormality" in nuclear plants in the affected area. South Korea's meteorological agency has warned that tsunami waves up to 0.3m could hit the eastern coast of the country between 18:29 to 19:17 local time (09:29 to 10:17 GMT).