John Braddock
An undersea volcano erupted near the Pacific nation of Tonga on Saturday, sending a series of waves sweeping into the capital Nuku’alofa and triggering tsunami advisories across the southwest Pacific as well as Australia’s east coast, Hawaii, Alaska and the US Pacific coast.
Japan and countries in Latin America were also impacted. Two women drowned at a beach in Lambayeque, in northern Peru, when 2-metre-high waves dragged a truck into the sea. No deaths have been reported in Tonga, but some of the archipelago’s 36 inhabited islands are still uncontactable after the disaster severed internet and phone lines.
Eruptions were heard as booms or “thumps” across the Pacific, in Fiji, Niue, Vanuatu, and in New Zealand and recorded some 2,000km away. Shock waves that traversed many thousands of kilometres were seen from space.
On Tonga, with a population of 105,000, cellphone videos posted to social media showed large waves washing ashore in coastal areas, swirling around homes, a church and other buildings. Data from the Pacific tsunami centre detected waves of 80cm (2.7ft). Satellite images showed a huge eruption, with a plume of ash, steam and gas rising above the Pacific.
Journalist Mary Fonua told TVNZ News on Saturday evening that the situation was “precarious.” Fonua said there were a series of “huge explosions” as the Hunga Tonga Hunga Ha’apai volcano, 65km from the main island, erupted at 5.30 pm. A tsunami warning for the entire country was issued, sending people rushing to higher ground.
Resident Mere Taufa told New Zealand website Stuff she and her family were preparing for dinner when they heard and felt the eruption. “It was massive. The ground shook, our house was shaking. It came in waves. My younger brother thought bombs were exploding nearby,” she said.
Witnesses described as many as 10 explosions, one after the other, with volcanic ash everywhere, and black smoke in the sky. Stuff reported people were “terrified” throughout the night, with no idea of what was happening, if the volcano would erupt again or if they faced more tsunamis.
On Sunday, ash was still falling with a huge blanket over the main island of Tongatapu. On the foreshore north of Nuku’alofa boats and large boulders were washed ashore. Besides flooding and extensive damage to property, contamination to the water catchments is a major issue. It could take weeks to fully restore phone and internet connections after a subsea communications cable to Fiji was cut.
There are growing concerns for at least 8,000 people in the Ha’apai group of islands nearest the volcano. The New Zealand Herald reported this morning that Rev ‘Ulufonua, a religious leader on Ha’apai, said there were no known casualties, but not all islands had been heard from.
The volcano has been active for most of the past week after a new volcanic vent began erupting in December. Earth imaging company Planet Labs PBC said satellite images showed the volcanic activity had re-shaped the area over the past month, with ash creating a growing island at the site of the volcano.
Authorities at home and abroad have done little to prepare the population for an emergency. According to the Matangi Tonga news site, early on Friday scientists had observed massive explosions, thunder and lightning near the volcano after it started erupting. Satellite images showed a 5km-wide plume rising into the air to about 20km.
The volcano erupted without warning on Saturday, after which tsunami evacuation sirens reportedly went off in Tongatapu. It is not clear how much time people had to move away from the beaches.
The Hunga-Tonga-Hunga-Ha’apai volcano is a massive caldera—a large depression formed when a volcano erupts and collapses. It is part of the string of volcanoes making up the Tonga Arc, formed by the Pacific tectonic plate subducting beneath the Indo-Australian tectonic plate.
The volcano has erupted regularly over the past few decades. In 2014-2015, a series of eruptions in the area created a small new island and disrupted international air travel for several days. According to Marco Brenna, a geologist at the University of Otago, it was not being actively monitored, either due to a lack of funding and resources in Tonga, or because earlier volcanic eruptions were relatively minor and it was not considered a priority.
The event impacted countries throughout the Pacific region. Authorities in nearby Fiji, Samoa and American Samoa issued warnings, and entire villages in parts of Fiji were flooded. In New Zealand, 120 people were evacuated in the country’s far north due to the tsunami threat coinciding with high seas from tropical cyclone Cody.