Satellite imagery shows the island of Hunga Tonga Hunga Ha'apai has grown in size while the underwater volcano erupts into its sixth day.
File image. Photo: Mary Lyn Fonua / AFP
Tonga's head geologist Taniela Kula has been monitoring the eruption all week, which erupted again this morning.
While observations have had to be kept to a distance, new satellite imagery shows the island's land mass has grown since Monday.
"The island has grown 300-600metres to the eastern side. So it has widened up a bit. [The debris] has been building up the island, building up the rim of the vents," Kula said.
Today's ash clouds had fallen back into the ocean in a 10km radius, he said.
The volcano has an active history, last erupting in 2014/15 and before that in 2009.
In 2015, Tongan government officials said eruptions at Hunga Ha'apai had formed a new island more than a kilometre long, joined to the existing island.
It has reportedly become a home for plants and birds.
More satellite footage will be sent to Kula and his team monitoring the eruption this afternoon.