A 7.1 magnitude has struck southern Japan, triggering a tsunami warning for several coastal areas.
Authorities fear the sea level could rise up to one metre on the Pacific coast of the western islands of Kyushu and Shikoku.
People have been told to stay away from the seashore and river banks.
Flights have been suspended at Miyazaki Airport, where there has been an evacuation.
A check is being made of the runway at the airport for any damage, according to the Ministry of Land, Infrastructure, Transport.
The earthquake, which occurred at 4.42pm local time today, is estimated to have been felt by more than 11 million people in Japan. A second tremor was felt about an hour later.
Japan Meteorological Agency recorded the magnitude as 7.1, with the epicentre at Hyuganada Sea.
It issued the tsunami warning for the coastal areas of Miyazaki, Kochi, Oita, Kagoshima and Ehime prefectures.
Specialist operator InsideJapan said none of its clients was in the affected area, which is approximately 1,128km from Tokyo.
“Both Customer Experience and Operations teams are on the ground continuing to monitor the situation, but as it stands all customers are continuing with their travels across Japan as planned and unaffected,” said a spokesperson.
“Although Japan is a country very used to earthquakes, our thoughts are with Japan, and anyone affected.”