The damage from Tonga’s volcanic eruption is still unclear
WORD CAME at last. Three days after Hunga Tonga-Hunga Ha’apai volcano in the Kingdom of Tonga erupted on January 15th, the prime minister’s office released a statement. The eruption was an “unprecedented disaster” for the archipelago and three deaths were confirmed. The blast created a vast ash cloud and led to a tsunami (two people drowned across the Pacific ocean in Peru). Explosions of volcanic gas were audible more than 2,000km away in New Zealand and plumes of gas rose more than 20km into the sky. In a biblical flourish, pebbles rained down on the Tongan capital, Nuku’alofa, located some 65km south of the volcano.Listen to this storyYour browser does not support the element.Enjoy more audio and podcasts on iOS or Android.The eruption was driven by subduction, a process whereby one of Earth’s tectonic plates (in this case the Pacific one) sinks beneath the edge of another (in this instance the Indo-Australian one). Hunga Tonga-Hunga Ha’apai sits within the “Ring of Fire”, a geological fault line encircling the Pacific. Tongans call the islands afflicted by the region’s frequent earthquakes those which “jump back and forth”.The volcano is 1,800 metres tall (measured from the sea floor) and takes its name from the two parts of the rim of its crater, or caldera, which, before the latest blast at least, rose above the sea: Hunga Tonga and Hunga Ha’apai. Shane Cronin, a volcanologist at Auckland University, reckons that the latest eruption probably came from the caldera itself.An eruption in December 2014 filled the gap between the volcano’s two islands with ash, joining them. “The island’s formation also probably seeded its destruction,” says James Garvin, chief scientist at NASA’s Goddard Space Flight Centre. “As it rose from the sea, layers of liquid magma filled a network of chambers beneath it.” When the magma in those chambers erupted on January 15th, the vast explosion in the seas and skies seems to have been coupled with an implosion in the rocks below as some of those chambers collapsed, undermining the caldera and its rim. Satellite images now show that only a chunk of one of the former islands remains visible.The true number of deaths among the country’s 100,000 people is unknown. So is the extent of damage to crops, villages and livelihoods. Communication with Tonga was possible only by satellite phone initially; the submarine cable that connects it to Fiji and thence to the outside world was severed. Repairs could take weeks as the closest repair vessel is 2,500km away. Flights in and out of Tonga were suspended at first, owing to ash on the international airport’s runway. Flights carrying aid are now arriving.New Zealand and Australia have sent surveillance flights over the archipelago to assess the damage. Reports suggest that roads and bridges have been destroyed, though the airport is intact. Grim satellite images show heaps of ash smothering entire islands. Emergency workers are handing out food, water and tents, according to the prime minister’s office. Water is particularly vital: many Tongans capture fresh rainwater from their roofs to drink. Ash has probably contaminated it.Navy ships carrying aid from Australia and New Zealand are on the way. The hope is they do not also carry covid-19. Tonga’s only case so far was caught at its border; one disaster must not lead to another. ■This article appeared in the Asia section of the print edition under the headline “A kingdom cut off”