A strong earthquake with a preliminary magnitude of 6.9 has hit southwestern Japan, the country's Meteorological Agency said Monday, while warning the public to stay away from coastal areas because of a tsunami threat.

Tsunami advisories were issued for Miyazaki Prefecture, where the quake was centered, in the southwestern island of Kyushu, as well as nearby Kochi Prefecture, shortly after the quake struck at 9:19 p.m. local time, according to the agency.

There were no immediate reports of damage. Residents in the coastal city in Kochi were told to evacuate as a precautionary measure.

Public broadcaster NHK TV said a tsunami, estimated to be as high as 1 meter (3.2 feet) high, reached land within 30 minutes of the quake. The waters detected at Miyazaki Port measured 20 centimeters (0.7 feet) high, the reports said.

The quake, centered at a depth of 30 kilometers (18.6 miles), shook a wide area in Kyushu, the southwestern main island, Japan's Meteorological Agency said.

Japan is frequently hit by earthquakes because of its location along the “Ring of Fire,” an arc of volcanoes and fault lines in the Pacific Basin.

NHK TV footage showed moving traffic and well-lit streets, meaning that electric power was still working. No problems were detected at the various monitoring posts for nuclear plants in the area.