A 7.2-magnitude earthquake that struck off the coast of Japan this afternoon has triggered a small tsunami, but with no reports of damage.

The quake hit at 1.54pm about 169 kilometres off the city of Sendai in northern Japan at a depth of 14 kilometres.

7.2 magnitude ... a USGS map of where the quake occurred. Credit:USGS

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The Japan Meteorological Agency issued a tsunami warning of up to 50 centimetres for the east coast of the main Honshu island.