Satellite photo of the eruption CIRA/NOAA/Handout via REUTERS
The massive explosion of Hunga Tonga-Hunga Ha’apai volcano in Tonga on Saturday was its most powerful eruption since AD 1100. The after-effects have been felt around the globe and the damage is still being assessed.
The volcano, located about 65 kilometres north of Tonga’s capital, Nuku’alofa, exploded with violent force at 5:10pm local time on 15 January. Satellite images show a mushroom cloud of ash billowing 30 kilometres high and later .
A sea level gauge at Nuku’alofa recorded a tsunami wave of 1.19 metres before it stopped recording, according to at the University of Newcastle in Australia. show waves crashing into houses in Tonga, and large waves also reached Japan, prompting evacuation orders, and Peru, where .
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The extent of destruction in Tonga is still uncertain because the country’s main undersea phone and internet cable was damaged. New Zealand prime minister Jacinda Ardern on 16 January that she had received reports of boats and large boulders washed ashore in Nuku’alofa and damage to properties, but that there was no news from other coastal areas. No deaths have been reported at this stage.
A New Zealand air force plane was deployed on 17 January to assess the damage, but its findings .
A final video of today’s explosive .
This shows data from all three weather satellites covering the area. From left to right: Korea’s GK-2A, Japan’s Himawari-8 and the US GOES-17.Fascinating to see the different perspectives.
— Simon Proud (@simon_sat)
Hunga Tonga-Hunga Ha’apai is 1.8 kilometres tall and 20 kilometres wide, but most of it is underwater, with only its top 100 metres poking out of the sea. It has been spewing ash intermittently and making small blast noises since
The pressure wave generated by the explosion blasted through the atmosphere at and was recorded crossing the , and . The resulting sonic boom was heard in nearby Fiji, in New Zealand and , over 9000 kilometres away.
The eruption also sparked almost above the volcano as bits of ash and atmospheric ice particles bumped into each other and generated electrical charges.
The Tonga volcano shockwave as heard from Fiji, nearly 1000 km away ?
video from
— Chris Combs (@DrChrisCombs)
— Chris Combs (@DrChrisCombs)
“Given the potential for further volcanic activity, there is also the potential for further tsunamis to be generated,” says Power.
Atmospheric sensors have detected large amounts of sulphur dioxide gas released by the eruption, which could cause acid rain to fall in Tonga and Fiji and affect crops and drinking water, says at the University of Auckland in New Zealand. However, the amount of sulphur dioxide isn’t enough to cause global cooling – an effect that was seen after the massive eruption of Mount Pinatubo in the Philippines in 1991, he says.
This is the most incredible loop that I have ever put together. eruption today with nearly 400k lightning events in just a few hours!
— Chris Vagasky (@COweatherman)
Cronin and his research team camped on Hunga Tonga-Hunga Ha’apai in 2015 and noticed that the surrounding coral reef was lifting up, suggesting that magma was building underneath the volcano and could cause an eruption in the near future.
Several small eruptions have occurred in the intervening years, probably as some of the growing pressure forced its way out of small fractures around the edge of the volcano, says Cronin. As the pressure built up further, it led to the breaking point on 15 January that caused the central part of the volcano to blow out, he says.
show that the above-water portion of the volcano is now almost completely obliterated. “You wouldn’t be able to camp on it now,” says Cronin.
His team found evidence of two previous mega-eruptions occurring on Hunga Tonga-Hunga Ha’apai in AD 1100 and AD 200, suggesting they occur roughly once every 1000 years.
The volcano has continued to erupt at a low level since 15 January and Cronin says he “wouldn’t be surprised if there were a few more explosive events” in the coming days or weeks. However, they are unlikely to be as powerful as the initial explosion, he says.
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