Shortcuts / 27 January 2022

Tonga and the Ring of Fire

The Hunga Tonga-Hunga Ha’apai undersea volcano erupted with an enormous force less than a fortnight ago, accompanied by cracking sonic booms, stratospheric volcanic ash and tsunami waves that travelled more than 10,000km. The volcano sits in an area prone to eruptions and earthquakes. So in this Squiz Shortcut, we’ll take a look at the zone known as the Ring of Fire, the big eruptions and earthquakes that have come from this region, and how Tonga is managing in the wake of the disaster.

When you say ‘Ring of Fire’, you’re not talking about the one that burns, burns, burns from wild desire, right?
Umm…no, but nice Johnny Cash reference. What we’re talking about is the path along the Pacific Ocean that’s characterised by active volcanoes and frequent earthquakes.

How many active volcanoes, exactly?
A lot… Three-quarters of the world’s ​​active volcanoes are dotted along the Ring of Fire, which is about 40,000km long.

Is it actually shaped like a ring?
Kinda… It’s more of an arc that follows the islands of Tonga and Vanuatu, heads west to Indonesia, north to the Philippines & Japan, then east to the US and down to South America. That follows the several tectonic plates.

Tec what now?
Strap yourself in… Tectonic plates are massive, oddly shaped slabs of rock that are underground ‘roots’ of continents. It helps to think of the globe like a cracked Easter egg.

The chocolate bits kinda fit together like a jigsaw, and that’s like Earth’s tectonic plates. They’re different types of rocks, some thicker than others, depending on the weight of the continents they’re trying to support.

Mmm easter eggs…
Focus, please. The point is those plates continue to move, sometimes towards and sometimes away from each other.

Right. And that movement underground causes action above ground too?
Yep. Sometimes plates dip underneath others, causing one of the plates to melt and become magma, which rises up and spews out through volcanoes. And in the areas where plates move sideways past each other, earthquakes tend to occur.

And that’s what’s happening in the Ring of Fire?
It is a pretty active area for eruptions and earthquakes, that’s for sure.  

The big one?
That would be the world’s deadliest eruption: Mount Tambora in Indonesia in 1815.

Take me through it.
That happened to the east of Bali. It’s thought to have been the most powerful eruption in 500 years and created a series of powerful tsunamis. About 120,000 people died.

Yeesh… So what’s another biggie?
Heard of Krakatoa?

Indeed I have
That volcano was located in the middle of the Sunda Strait – that’s in between the island of Java (which is home to the capital Jakarta) and the northern island of Sumatra. The eruption was so loud that it could be heard thousands of kilometres away and it generated a 37-metre high tsunami. It was such a momentous event it brought on a cooling event in the Northern Hemisphere.

How does that work?
It has to do with the sulphur dioxide released in an eruption. In Krakatoa’s case, the aerosol particles from sulphur dioxide created a global dimming effect, where less of the sun’s radiation is able to reach the surface of the Earth.

Sounds eerie… Indonesia seems to cop a lot of trouble from volcanoes… 
And earthquakes, like the underwater quake that struck on Boxing Day in 2004 off the northwestern coast of Banda Aceh in Indonesia, where the Indian and Australian tectonic plates meet.

I remember that. Remind me of the facts again… 
The earthquake registered 9.1 on the Richter scale – a whopper. The quake caused the ocean floor to rise by as much as 40m, and that triggered a massive tsunami. Huge waves hit Aceh and rolled over the coastlines of Thailand, Sri Lanka – and 8 hours later, on the coast of South Africa.

So it had a massive impact…
About 230,000 people died across the world.

And was the earthquake and tsunami that hit Japan in 2011 related to this? 
It was in the Ring of Fire zone, so yes. The one you’re talking about hit Sendai off the northeastern coast of Honshu.

It caused the meltdown of the Fukushima nuclear power plant, right?
Right. The earthquake was one thing, but the resulting tsunami breached the seawall and flooded the reactors. There were 3 nuclear meltdowns and in total, that disaster saw 20,000 die or go missing, and close to half a million were forced to evacuate. It cost Japan US$360 billion.

Ok, let’s move on to the most recent eruption in Tonga.
Sure – it’s right up there as one of the world’s big eruptions. And NASA says it was hundreds of times more powerful than the atomic bomb the US dropped on Hiroshima during World War II.

Take me through what happened.
Well, before the eruption, the Hunga Tonga-Hunga Ha’apai volcanic island was made up of 2 separate islands joined by new land formed in 2015.

Hold on – new land?
Yep, it’s hard to get your head around… But what NASA says is that according to their satellite images, the eruption was so powerful that all the new land is gone, along with “large chunks” of the two older islands.

And it set off a huge tsunami?
It sure did. Reports say that Tonga was hit by a 15-metre wave, and the tsumani was recorded here in Australia and other nations thousands of kilometres away.

How much damage did it cause?
As you can imagine, quite a bit… The satellite images taken in the days after the eruption showed inland pools of saltwater and blankets of grey ash. There’s a long way to go in assessing the damage and losses, and the Tongan Government says it’s an “unprecedented disaster”.

What was the death toll?
So far it’s low – 2 Tongans and one British woman are confirmed to have died in Tonga, and 2 people in Peru died in rough surf waters thanks to the tsunami. 

So aid is on the way?
Yes, but a big issue is keeping COVID out. The kingdom has had one reported case during the whole pandemic, and they want to keep it that way.

Nothing’s ever easy…
Nope, but aid groups are calling on Australians to help the Tongan community as the recovery efforts continue over the coming months.

Squiz recommends:

Tonga’s volcano eruption in pictures – The Guardian

Aceh Tsunami Museum

Australian Red Cross donation page

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