Tonga: What actually happened when Volcanic Mushroom Plume

"It takes roughly 900-1000 years for the Hunga volcano to fill up with magma, which cools and starts to crystallize, producing large amounts of gas pressure inside the magma"

On 15th January 2022, the entire South Pacific Islands got a shock of having effects of Hunga volcanic eruption at Tonga (part of Polynesian archipelago comprises of 176 islands, where 36 of which are inhabited), that released a cloud of ash and volcanic gases of about 30 km into the sky and produce tsunami waves throughout the Pacific Islands.

The Hunga-Tonga-Hunga-Ha’apai volcano is located 40 miles north of the capital, Nukualofa. The Hunga volcano is about 1,800 meters high and 20 kilometres broad and is a part of a volcanic system that stretches from New Zealand to Samoa. The volcano erupted three times in the week on 20th  December 2021, 13th and 15th January 2022, the last one is seen as the greatest in recent history.

There was an enormous eruption that produced a 30 km-high cloud of ash and gas and led to tsunami advisories across the Pacific and surrounding nations; a large number of Tongans faced water, power, communication and air travel was disrupted.

- Advertisement -

The smoke plume erupted from the volcano, noticed shock waves and witnessed powerful electric storms in the ash cloud. Many debates around this issue need to be enlightened, so this op-ed shall try to review the discussions around the issue.

Is it a ‘Once-in-a Millennium’ Event?

Historical records stated many past volcanic eruptions had put the world into shock, especially the 1991 Pinatubo eruption in the Philippines. However, on the latest eruption, Shane Cronin, a volcanology professor at the University of Auckland in New Zealand, stated the explosion was a “once-in-a-millennium” occurrence for the volcano as “It takes roughly 900-1000 years for the Hunga volcano to fill up with magma, which cools and starts to crystallize, producing large amounts of gas pressure inside the magma… As gases start to build up pressure, the magma becomes unstable. Think of it like putting too many bubbles into a champagne bottle — eventually, the bottle will break.” (Corryn Wetzel, 18/01/2022). Other experts believed it was the largest eruption in the last three decades. 

volcanic eruption; Image Source: @CANVA

Others believe that this catastrophe might see as simply warm-up as this vulcanized inside the Pacific Ring of Fire, which is the part of some active world’s volcanoes. The Pacific Ring of Fire stretches in the form of a horseshoe from the southern point of South America along the West Coast of North America, through the Bering Strait, past Japan, and into New Zealand (Pannett et al., Washington Post, 20/01/2022).

It is an active zone where the Pacific Plate collides with many other tectonic plates that creates the bulk of the world’s volcanism and earthquakes; it is considered to have three-fourths of the world’s active volcanoes. This eruption produced a shockwave that travelled across the globe, which was recorded as a pressure wave and an acoustic signal. 

According to NPR, NASA experts assessed the blast’s force to be ten megatons, or more powerful than a nuclear weapon (Pannett et al., Washington Post, 20/01/2022) that is many times more powerful than the bomb dropped on Hiroshima. The report further added, based on experts suggestions, that the Tongan volcano is capable of releasing an explosion of such magnitude once every 1,000 years, comparable to a weapons-grade chemical bomb. Some experts suggested this eruption will have long-lasting damage to coral reefs, erode coastlines and disrupt fisheries (Aljazeera, 18 Jan 2022). Warning were also issues about the acid rain around the Pacific Islands that may have an impact on some crops and fruits vegetations.

- Advertisement -

The eruption also led to inflicting a large volume of material into the stratosphere, including sulphur dioxide (SO2 gas), as per reports, this shall have a significant impact on the climate. Experts stated, “SO2 reflects solar radiation back to space, and can thus have a cooling impact on the climate system, especially for eruptions of this nature in the tropics, where the bulk of the incoming radiation is absorbed.” (Nevada Today, 27 January 2022). Other reports suggest that SO2 will not have any significant impact on the global climate, but it is not clear that there may be further eruptions that can increase the intensity of SO2 concentrations (Ramesh, The Print, 22/01/2022). 

volcanic eruption; Image Source: @CANVA

Tonga is situated on a fault or junction where the Pacific plate is sinking under the Australian plate, where seduction causes warm water in the sinking plate to rise up and mix with magma, causing it to become vicious; that holds a lot of the hot water as bubbles, causing pressure to build up for eruptive events to occur (Ramesh, The Print, 22/01/2022). The eruption scale is vast and yet to be analysed its major causes by experts. 

Conclusion: Small Vulnerable Islands

As a resident of the Pacific Islands, I have enormous sympathy with our Tonga fellow brothers and sisters who had faced the wrath of these devastating volcanic eruptions. These islands are vulnerable to volcanic eruptions, and the experts have diverse opinions about the impact of this volcanic eruption. Still, the answers are stored in future to see the consequences. It would be too soon to assess its actual impact. Pacific Islanders and the entire world need to be cautious of any future events and necessary precautions.

Author: Dr Sakul Kundra, A.HOD Department of Social Science, College of Humanities and Education, Fiji National University.

Dr Sakul Kundra; Picture Source: Supplied
Dr Sakul Kundra; Picture Source: Supplied

Disclaimer: The views expressed are his own and not of The Australia Today or his employer. For comments or suggestions, email. dr.sakulkundra@gmail.com