Japan issued a tsunami advisory for some coastal regions early Monday following a series of shallow earthquakes in the Izu islands in the Pacific Ocean but there were no immediate reports of damage from the minor waves generated, seismologists said.
Tsunami waves of 60 centimetres hit Hachijojima island, 280 kilometres south of Tokyo, while ones of 40cm and 20 cm were recorded in western Kochi prefecture and southern Miyazaki prefecture, respectively, according to the Japan Meteorological Agency.
No damage has been reported, the JMA said, but Tateyama city of Chiba, near Tokyo, urged residents in coastal areas to evacuate after the advisory.
JMA official Toshihiro Shimoyama warned during a press conference that "it is dangerous in the sea and near the coast".
"Please get out of the sea and stay away from the coast."
Shimoyama said the JMA "haven't been able to pinpoint the cause" although it assumed a quake had generated the tsunami waves.
The US Geological Survey, however, reported a series of shallow quakes in the Izu islands, with the strongest a 5.4 magnitude tremor recorded at 5:17 am (2117 GMT Sunday) around 551 kilometres south of Shimoda.
The latest advisory comes after Japan observed a one-metre tsunami near the Izu islands after a magnitude 6.5 quake last week.