Japan's prime minister today cancelled a planned trip to Central Asia after earthquake experts warned that the country should prepare for a possible strong tremor.
"As the prime minister with the greatest responsibility for managing the crisis, I have decided to stay in Japan for at least a week," Fumio Kishida told reporters.
The head of government was due to visit Kazakhstan, Uzbekistan and Mongolia and had planned to attend a summit of five countries in the region.
At least 13 people were injured in Thursday's earthquake measuring 7.1 on the open Richter scale in south-west Japan, said the authorities, who warned of the possibility of strong aftershocks.
The Japan Meteorological Agency (JMA) warned that this event appears to be linked to a future larger earthquake on the Nankai fault, one of the world's most active seismic hotspots and where a strong tremor is expected to occur in the coming decades.
"The probability of another strong earthquake is higher than normal, but this does not indicate any certainty," said the JMA.
This is the first time an alert of this kind has been issued since a new system was set up in 2011.
The most powerful earthquake ever recorded in Japan, of magnitude 9, occurred on 11 March 2011 on the north-east coast and triggered a tsunami that left around 20,000 dead or missing.
The Japanese government had already stated that there was a 70 per cent chance of a strong earthquake hitting the country in the next 30 years.
A quake that could affect a significant part of Japan's Pacific coast and threaten around 300,000 people, according to experts.
Japan is located on the so-called "Ring of Fire" in the Pacific, an area of great seismic and volcanic activity, where thousands of earthquakes are recorded every year, most of them of weak to moderate magnitude, and with close to 120 active volcanoes.
