Aid efforts are continuing as the Kingdom of Tonga recovers from the recent volcanic eruption of Hunga-Tonga-Hunga-Ha’apai. The violent blast generated a Tsunami and blanketed the islands in volcanic ash. Video / Supplied
University of Otago volcanologist Dr Marco Brenna has been to the area of Tonga that is now the focus of world attention and concern.
He was part of a team that studied the rocky Hunga-Tonga and Hunga-Ha'apai islands in 2015 and a cone that had recently emerged and connected the islands.
Brenna was somewhat surprised by the explosiveness of the eruption at the weekend and he could see from satellite imagery that the area of his visit had been obliterated.
"It's astonishing to see such a large eruption," Brenna said.
It was unlikely more eruptions would occur on a similar scale, he said.
"As the volcanic edifice will have become unstable, however, it is possible that further collapses will occur, generating tsunamis."
The impact could be relatively long-lasting, depending on how much volcanic ash had settled on land.
"Volcanic ash, despite the name, is dense as rock and can cause significant damage to structures, power lines and communications.
A composite of satellite images taken by Himawari-8, a Japanese weather satellite operated by Japan Meteorological Agency. Images / NICT via AP
"It is also toxic because it contains chemicals such as sulfur, chlorine or fluorine, and it can therefore affect water supplies."
Brenna said inhaling ash could damage people's lungs.
Large amounts of volcanic particles suspended in the water could affect fisheries, he said.
New Zealand's volcanoes were well monitored and this put the country in a better position to prepare or respond if a very large eruption was to occur here.
Only Whakaari/White Island had the potential to generate tsunamis.
