A strong earthquake with a preliminary magnitude of 7.1 on the Richter scale shook off southwestern Japan on Thursday, the Japan Meteorological Agency said. There were no immediate reports of casualties or major damages from the 4:43 pm (0743 GMT) quake. The weather agency issued a tsunami advisory for waves of up to one meter for coastal areas of Miyazaki, Kochi, Oita, Kagoshima and Ehime prefectures. According to the agency, a 50-cm tsunami was observed along the coast of Miyazaki Prefecture. There were no abnormalities at nuclear power facilities in the areas, plant operators said. Shinkansen bullet train services in the region were suspended, the operator said. The tremor originated at a depth of about 30km off the eastern coast of Japan's southern main island of Kyushu, about 1,000 km southwest of Tokyo. The quake measured lower 6 on the Japanese seismic intensity scale of 7 in the city of Nichinan in Miyazaki Prefecture. The weather agency defines an intensity of lower 6 as strong enough to most heav y and unbolted furniture moves and falls. At an emergency press conference in Tokyo, the weather agency warned that quakes of up to lower 6 - upper 5 could occur in the area for about a week, urging the residents to remain on guard against possible seismic activities. Source : Kuwait News Agency