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How big was the Tonga eruption?

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Re: How big was the Tonga eruption?

#101

Post by nabla9 »

Globally event appears unlikely to have a significant cooling effect on temperatures globally, h

>"However, to date, it injected 'only' 0.4 Tg (400,000 tonnes) of sulphur dioxide into the atmosphere, which is not enough to result in significant surface cooling for this individual eruption. "Unless further eruptive activity occurs, we should not detect significant surface cooling. At present, hazards related to ash fallout are really the number one concern."

https://news.abs-cbn.com/spotlight/01/19/22/explainer-tonga-...

Local environmental harm: https://www.reuters.com/business/environment/tongas-volcanic...

Re: How big was the Tonga eruption?

#103

Post by capitainenemo »

bt1a wrote: post #89
lelandbatey wrote: post #47

Earlier quoted context omitted.

Yes, they did use transparent shadows. You can tell because the images are not GIF's, they're actually a sequence of PNG images overlayed atop other PNG images. There's the base satellite image of the area, then the frames-of-explosion-with-transparency overlayed atop them. You can confirm this by right clicking on the image and choosing "open image in new tab", which will (usually) open this final frame in a new tab…

I tried to save one of the "gifs" to share with a friend and was quite upset that I found myself with a png. Interesting technique. Do you think this was done to have better quality animated images? GIF compression isn't amazing (relative to WebM at least)

I mean, they could have used APNG at this point. https://caniuse.com/apng

Doesn't compress stuff like that super well but no worse than a sequence of PNGs.

I feel if you're gonna use JS animation anyway, you could just use 2 jpegs, one for masking and a canvas.

Hm. Webp is doing darn well these days too. https://caniuse.com/webp

Avif isn't an option yet.

Re: How big was the Tonga eruption?

#104

Post by dylan604 »

bt1a wrote: post #89
lelandbatey wrote: post #47

Earlier quoted context omitted.

Yes, they did use transparent shadows. You can tell because the images are not GIF's, they're actually a sequence of PNG images overlayed atop other PNG images. There's the base satellite image of the area, then the frames-of-explosion-with-transparency overlayed atop them. You can confirm this by right clicking on the image and choosing "open image in new tab", which will (usually) open this final frame in a new tab…

I tried to save one of the "gifs" to share with a friend and was quite upset that I found myself with a png. Interesting technique. Do you think this was done to have better quality animated images? GIF compression isn't amazing (relative to WebM at least)

Probably more along the line of they have some library that uses PNG sequences. Maybe even as simple as a slideshow with short durations. It's a newsy site. They don't have a lot of control over what their CMS/publishing platform can do. Someone probably had a clever idea on how to use something existing in a way not envisioned when created.

Re: How big was the Tonga eruption?

#106

Post by Retric »

mytailorisrich wrote: post #44
herpderperator wrote: post #20

Did the the ocean influence the ease of expansion of the explosion? Or hinder it? We are comparing an underwater explosion to one on land, and I'm wondering if it's directly comparable.

From what I've read it seems that the ocean exacerbated the explosion: the hot magma caused water to vaporize and created a steam explosion. I've read about a 70x volume expansion and that the top altitude of the plume was steam. On the other hand, the ocean might have captured some of the ash (?)

It should have also significantly reduced the temperature of the resulting ash cloud which reduced the quantity of particulate matter in the upper atmosphere. Which presumably reduces how much short term global cooling you get from the eruption.

Re: How big was the Tonga eruption?

#107

Post by depereo »

RowanH wrote: post #79

Heard it go bang, 2600km away, echoing through the hills around our place at the top of the South Island of New Zealand. That's pretty staggering to think about it. Then to see other peoples Home Assistants around the world pick up the change in pressure on opposite sides of the planet. Mental, just mental...

My colleague's backyard weather station picked up the pressure wave in Christchurch several times as it repeatedly circled the globe.

Sea levels in the upper south were a little 'odd', trending higher and more variably than usual, even if not by that much, for a week.

Re: How big was the Tonga eruption?

#109

Post by pmayrgundter »

cletus wrote: post #95

Someone else estimated the Tonga explosion at 10 megatons [1] and it was heard thousands of miles away. Bear in mind, humans have detonated nuclear weapons larger than this, most famously the Tsar Bomba [2] at 50 megatons. Compare this to something not that long ago: Krakatoa, estimated at 200 megatons [3]. Then compare this to the Year Without Summer (536 AD) [4]: > Falling in the time known as the 'Dark Ages', the…

Maybe interesting, I keep a list of large energy events/stores for thinking about the scale of global catastrophes.

Looks like this Tonga eruption is VEI5 or 6, so between St Helens and Pinatubo.

Comments appreciated in the doc!

- Mt. Toba 74kya, VEI 8/M8.8 eruption energy: 1e21-1e22 Joules

- M8 Volcanoes once every million years, but M7 yield > 10x more energy over time.

- Global Warming: 7.88e21 Joule/year

- Hiawatha Crater (Pleistocene, possibly 12kya) impact energy: 3e21 J

- Hurricane (1% kinetic, 99% latent heat): 1e21 J

- Human energy production 2013: 5.7e20 J/year

- Mt. Tambora 1815, VEI 7 eruption energy: 1.3e20 J

- Largest earthquakes 2: 1e19 J

- World nuclear weapon stockpile yield (extrapolated from USA): 16e18 J

- United States nuclear weapon stockpile yield 2020 (~2Gt TNT): 8.3e18

- Mt. Pinatubo 1991, Krakatoa 1883; VEI 6 eruption energy: 8.3e17 J

- Mt. St. Helens 1980, VEI 4 eruption energy: 1e17 J

https://docs.google.com/document/d/14EslUTRCwOgc_EobxH6X5e01...

Re: How big was the Tonga eruption?

#110

Post by datavirtue »

zo1 wrote: post #90
CoastalCoder wrote: post #75

Earlier quoted context omitted.

I'm curious if this would cause a noticeable change in the pH of those waters, and if that could be a good basis for estimating how much ash was captured.

I wonder how many tonnes of fish got destroyed, cooked, or otherwise thrown many kilometers into the air.

That sounds delicious
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