Around 230,000 people were advised to evacuate across eight prefectures due to the tsunami risk, NHK reported. The alert included areas hit by the deadly 2011 tsunami.
Ten boats were capsized in Kochi prefecture on Shikoku island in southern Japan, NHK said, and Japan Airlines cancelled 27 flights at airports across the country.
Tsunami waves were observed in Tonga’s capital and the capital of American Samoa, a US-based tsunami monitor said, following the eruption at 0410 GMT of the Hunga Tonga-Hunga Ha’apai underwater volcano.
The volcano, which lies about 65 km (40 miles) north of Nuku’alofa, caused a 1.2-metre (four-foot) tsunami wave, Australia’s Bureau of Meteorology said.
The bureau said it continued to monitor the situation but no tsunami threat had been issued to the Australian mainland, islands or territories.
In a briefing, a Japan Meteorological Agency official urged people not to go near the sea until the tsunami advisory and more serious tsunami warnings had been lifted. The warnings – the first in more than five years – covered several specific areas.
