Japan earthquake: Strong 5.9 magnitude quake sparks terrifying tsunami warning

A tsunami wave with a height of 20cm has been observed at Kozushima Port, according to a local news outlet via NTV News, while a tsunami of 50cm was observed in Hachijo-jima, Hachijo Town, Tokyo.

Japan's meteorological agency issued a tsunami advisory this morning to remote islands south of Tokyo after an earthquake that may have been triggered by volcanic activity. The Japan Meteorological Agency said a magnitude 5.9 quake hit off the Izu Islands and tsunami waves up to one metre above tide levels could occur on the coasts of the Izu and Ogasawara island chains. The US Geological Survey measured the quake's strength at 5.6 magnitude.

The agency predicted small swelling of waves along the southeastern Pacific coasts but said there is no danger from it, adding that a tsunami of about 50 centimetres (about 20 inches) was detected in the Yaene district on Hachijo Island about 30 minutes after the quake. Smaller tsunamis have been detected on three other islands - Kozushima, Miyakejima and Izu Oshima, the agency said.

Residents on Hachijo said they did not feel the quake and only heard the tsunami advisory, Japan's NHK public television said. Fumihiko Imamura, a Tohoku University seismologist, said the tsunami on Tuesday (24 September) is believed to be related to undersea volcanic activity.

He said a larger tsunami could arrive much later and urged coastal residents to keep their guards up while the advisory is in place. About 21,500 people live on the islands in the Izu group and about 2,500 on the Ogasawara Islands. Japan sits on the Pacific "Ring of Fire," a line of seismic faults encircling the Pacific Ocean, and is one of the world's most earthquake and tsunami-prone countries.