TOKYO (AP) — 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, in Shikoku island, 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 some coastal areas were told to evacuate as a precautionary measure. One man was slightly injured in Kyushu after falling down some stairs, NHK reported. Trains stopped running in Miyazaki Station, stranding passengers.

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.

Experts at the meteorological agency were meeting late Monday to gauge how the latest temblor may be related to the so-called Nankai Trough quakes.

The term refers to a wide region believed to be prone to periodic major quakes. A Nankai Trough quake off Shikoku in 1946 killed more than 1,300 people. The area was hit by a 7.1 magnitude quake in August last year.