The warning, issued on Thursday, advises residents to be alert but not to evacuate.
The epicenter of the 7.1 quake was located at the edge of the Nankai Trough, a seismic hotspot known for producing devastating earthquakes. Experts warn of a 70-80% chance of a magnitude 8 or 9 quake striking the trough within the next 30 years. Such an event could result in catastrophic damage and a massive tsunami.
While emphasizing that a major quake is not imminent, Japanese officials have urged residents to prepare by checking evacuation routes and ensuring adequate supplies. The warning will remain in place for a week.
The country has a history of powerful earthquakes, most notably the 2011 Tohoku earthquake and tsunami, which caused widespread devastation. (ILKHA)