Tokyo, Aug 8: An earthquake with a preliminary magnitude of 7.1 hit southwestern Japan on Thursday, with tsunami advisories issued for Kochi, Miyazaki and other prefectures, Japan’s weather agency said.

The 4:43 p.m. quake occurred at a depth of around 30 kilometres off Miyazaki and registered lower 6 on the Japanese seismic intensity scale of 7 in the city of Nichinan in the southern part of the prefecture, the Japan Meteorological Agency said. The magnitude was revised from 6.9.

The agency said it has started investigating whether there is a link between the temblor and a potential massive trench-type earthquake along the Nankai Trough stretching from off western to central Japan.

The tsunami advisories were issued for Kochi, Ehime, Oita, Miyazaki and Kagoshima prefectures.

A Tsunami with heights of around 50 centimetres and 20 cm was observed in Miyazaki and southwestern Kochi, respectively, the agency said.

No abnormalities were found at Ikata and Sendai nuclear power plants in Ehime and Kagoshima prefectures, their operators said.

Services on the Kyushu and Nishi Kyushu shinkansen bullet trains were temporarily suspended due to the quake, the operator said.

The agency warned that quakes with a seismic intensity of around lower 6 could happen for about a week.

As of January, the government’s Earthquake Research Committee forecasted a 70 to 80 per cent likelihood that a quake with a magnitude of 8.0 to 9.0 will occur near the Nankai Trough within the next 30 years.

In 2012, the government estimated that up to 323,000 people could die in the megaquake. (Kyodo)