Massive Hunga Tonga volcanic eruption seen from space and subsequent tsunami affected 11 countries and terrotories
On 14 January 2022, a very large eruption on Hunga Tonga–Hunga Haʻapai, an uninhabited volcanic island of the Tongan archipelago in the South Pacific Ocean, began. Hunga Tonga is 65km north of Tongatapu, the country's main island and is part of the highly active Tonga–Kermadec Islands volcanic arc, a subduction zone extending from New Zealand north-northeast to Fiji. The eruption caused tsunamis in Tonga, Fiji, American Samoa, Vanuatu and along the rim of the Pacific Ocean, including damaging tsunamis in New Zealand, Japan, the United States, the Russian Far East, Chile and Peru. At least three people were killed and many remain missing in Tonga from tsunami waves up to 15m high. Two people drowned in Peru when a two-metre wave struck the coast. Preliminary data indicated that the event was probably the largest volcanic eruption in the 21st Century and the largest since the 1991 eruption of Mount Pinatubo.
Little information was made available on the extent of damage and casualties from Tonga due to communication issues involving a damaged undersea cable. Video footage showing waves hitting coastal areas in Tonga was reported by Sky News. Atatā, a small island off the capital city, was reportedly submerged and rescue operations were being carried out. Images confirmed that most of the island has been wiped out; the New Zealand Defence Force described the damages as "catastrophic." There were some reports of residents in Tonga struggling to breathe as a result of the ash.
All structures were destroyed on Mango Island. Only two buildings remained intact on Fonoifua Island and Nomuka Island suffered major damage. Twenty-one homes were destroyed and another 35 were seriously damaged on Tongatapu's west coast. Eight homes were demolished and 20 seriously damaged in Nukuʻalofa. ʻEua Island saw the loss of two homes and 45 damaged. An assessment by the United Nations Institute for Training and Research (UNITAR) revealed extensive damage on Atatā Island; at least 72 buildings were affected by the tsunami and the whole island was blanketed by ash.
Rescue operations immediately followed on Atatā Island, which is located off the main Tongan island near Nukuʻalofa, after the small island was reportedly submerged by the tsunami. A Facebook post by the Royal Sunset Island Resort on the island said all residents were accounted for and safely evacuated.
A New Zealand Government official in the capital Nukuʻalofa said extensive damage occurred on the waterfront of the city, as it was severely hit by the tsunami. Acting High Commissioner Peter Lund said that several people were unaccounted for following the eruption and tsunami. Tattoo parlour owner Angela Glover, a British resident in Tonga was among the people missing, swept away by the tsunami when it hit Nukuʻalofa. Glover's body was later found. Though the extent of the damage in Tonga is still not clear, a blanket of thick ash has contaminated water supplies, cut off communications and prevented surveillance flights, making it difficult for relief efforts to begin.
Another fatality was confirmed by the Ministry of Foreign Affairs and Trade on 18 January. Lund added that there is an unconfirmed third death from the tsunami. This third death was identified as a local resident and the Tongan Government has confirmed three deaths were the result of the tsunami.
Thick ash on an airport runway was delaying aid deliveries to the Pacific island nation of Tonga, where significant damage was being reported days after a huge undersea volcanic eruption and tsunami.
New Zealand's military is sending much-needed drinking water and other supplies but said the ash on the runway will delay the flight at least a day. A towering ash cloud since Saturday’s eruption had prevented earlier flights. New Zealand also sent a navy ship to Tonga Tuesday with another planned to leave later in the day and pledged an initial 1 million New Zealand dollars (€590,000) toward recovery efforts.
Australia sent a navy ship from Sydney to Brisbane to prepare for a support mission if needed.
Communications with Tonga have been extremely limited, but New Zealand and Australia sent military surveillance flights to assess the damage on Monday, with aerial photos showing the vibrant Tongan landscape transformed by the ash into a grey moonscape.
UN humanitarian officials and Tonga’s government “report significant infrastructural damage around Tongatapu,” U.N. spokesman Stephane Dujarric said.
Research into these earlier eruptions suggests this is one of the massive explosions the volcano is capable of producing roughly every thousand years.
Why are the volcano’s eruptions so highly explosive, given that sea water should cool the magma down?
If magma rises into sea water slowly, even at temperatures of about 1200 degrees Celsius, a thin film of steam forms between the magma and water. This provides a layer of insulation to allow the outer surface of the magma to cool.
But this process doesn’t work when magma is blasted out of the ground full of volcanic gas. When magma enters the water rapidly, any steam layers are quickly disrupted, bringing hot magma in direct contact with cold water.
Volcano researchers call this “fuel-coolant interaction” and it is akin to weapons-grade chemical explosions. Extremely violent blasts tear the magma apart. A chain reaction begins, with new magma fragments exposing fresh hot interior surfaces to water and the explosions repeat, ultimately jetting out volcanic particles and causing blasts with supersonic speeds.
Sources: Euro News, Scientific American