Japan hit by 7.1-magnitude earthquake, tsunami alert issued

Japan is among the world's most earthquake-prone countries, sitting atop four major tectonic plates along the Pacific "Ring of Fire".

A powerful earthquake with a preliminary magnitude of 7.1 struck off the coast of Kumamoto on Japan's southern main island of Kyushu on Tuesday afternoon, prompting the Japan Meteorological Agency (JMA) to issue a tsunami advisory.

The quake struck at 4:27 pm local time (0727 GMT) at a depth of 10 kilometres (6 miles) beneath the seabed, according to the JMA. The agency said the shaking reached the maximum intensity of 7 on Japan's Shindo seismic scale, which measures the strength of ground shaking.

Authorities warned that tsunami waves of up to one metre (three feet) could reach parts of the coast at around 5:00 pm local time. Public broadcaster NHK reported that waves of up to that height may already have been recorded in some areas.

Japan is among the world's most earthquake-prone countries, sitting atop four major tectonic plates along the Pacific "Ring of Fire". The country experiences hundreds of earthquakes every year and accounts for nearly 18% of the world's seismic activity. While most quakes are relatively minor, their impact depends on factors such as location and depth.

More recently, a magnitude 7.2 earthquake struck northern Japan on June 25 without causing any deaths or major damage. In April this year, a stronger 7.7-magnitude earthquake in northern Japan injured at least 10 people and shook high-rise buildings in Tokyo, prompting authorities to issue a week-long advisory warning of an elevated risk of earthquakes measuring magnitude 8.0 or higher.