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How big was the Tonga eruption?

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Re: How big was the Tonga eruption?

#171

Post by crakenzak »

lambda_dn wrote: post #165

Wondering if any ships were destroyed by the eruption the scale makes me think there had to be? Could Volcano eruptions be Earth's way of stabilizing climate change? i.e. sea water gets warmer and is no longer keeping the eruptions from occurring. Then the eruptions causes a drop in temperature due to the ash in the atmosphere?

> Then the eruptions causes a drop in temperature due to the ash in the atmosphere?

Interesting, this prompted me to read[1] into how it works and made me interested in why we don't pump sulfur dioxide into the atmosphere to help cool down the planet and buy us more time to transition off of CO2/CH4 emitting processes? Is it cost prohibitive? We already cloud seed pretty often so there's infrastructure in place for a large scale operation?

[1] https://scied.ucar.edu/learning-zone/how-climate-works/how-v...

Re: How big was the Tonga eruption?

#172

Post by thaumasiotes »

distribot wrote: post #138
divbzero wrote: post #119

Earlier quoted context omitted.

The Pacific Ocean is ginormous (I think that’s the technical term?) I often find myself surprised when I spin a globe (physical or virtual) and compare the expanse of the ocean to my neighborhood of the planet. The scale also makes the history of Polynesian seafaring all that more incredible.

Yes, they had incredible techniques. They could detect a remote island by the way the swell is disrupted. Also recently read about Magellan's voyage and it is remarkable that they made it.

> Also recently read about Magellan's voyage and it is remarkable that they made it.

Well, they didn't.

https://en.wikipedia.org/wiki/Ferdinand_Magellan#Voyage

> Of the 270 men who left with the expedition, only 18 or 19 survivors returned.

A 93% mortality rate really isn't a success by any metric. Losing 80% of your ships is nothing to be proud of either.

Re: How big was the Tonga eruption?

#173

Post by robertwt7 »

That is huge! As someone who originally came from tropical country, volcano eruption sucks even if you live far away from it. The dust, the earthquake, tsunami warnings, etc. hopefully everyone who is affected is doing fine

Re: How big was the Tonga eruption?

#174

Post by subsubzero »

Curious if this will cause a slight cooling of the earth's air temperature due to increased volcanic particles in the air. I had no idea of the size of this eruption and it looks absolutely enormous based on this article. It didn't mention how many metric tons were ejected into the atmosphere

Here is an article saying that after a eruption the air temperature rapidly cools for a while. Lets hope this doesn't wreck crop production.

https://www.scientificamerican.com/article/volcanoes-cooled-...

Re: How big was the Tonga eruption?

#175

Post by lnwlebjel »

sandworm101 wrote: post #140
TheOtherHobbes wrote: post #135

Earlier quoted context omitted.

US tsunami monitoring has a record. https://www.tsunami.gov/previous.events/?p=03-19-09-Tonga

A tsunami is a wave. Not sea level. Waves literally come and go over a period of seconds to minutes. They wobble back and forth without actually moving much water. Sea levels move on the order of hours and days and involve the physical movement of literally hundreds of cubic-miles of water. Raising or lowering a sea level measurement (not a temporary wave) requires far more energy than a volcano. From the link: "List…

Think of it more like a very long period wave, much like a tide, but on a much shorter time period than the tide. Tides, waves (periods on the order of seconds), and tidal waves (or tsunamis) are all fluctuations in sea level. Water can be moved when the waves encounter enclosed bays or harbors. Think of the water level dropping 3 ft over 20 minutes in front of a harbor entrance and imagine the currents that can result.

Here's an example of observations from coastal California (red line shows sea level measured every 6 minutes: https://tidesandcurrents.noaa.gov/waterlevels.html?id=941211...

It is truly amazing - I'm not surprised that it's hard to believe.

Re: How big was the Tonga eruption?

#176

Post by manquer »

phist_mcgee wrote: post #148
michilehr wrote: post #142

My cheap weather station has recorded the blast wave three times. https://michilehr.de/the-eruption-of-hunga-tonga-volcano-and...

I find the mix of your commas and periods in numbers a little confusing. >305,8 m/s but also 8.7m and ~1.4 hPa. I know that Europeans have a different notation to Americans, but is there a rule here I am missing?

While OP here made a mistake, some countries use mixed systems depending on what it is used for . Switzerland for example uses comma for normal numbers and dot for currency alone.

https://en.wikipedia.org/wiki/Decimal_separator#Examples_of_...

Re: How big was the Tonga eruption?

#177

Post by gnramires »

Railsify wrote: post #146
mkl wrote: post #127

Earlier quoted context omitted.

Even exactly on the other side of the world, the sound will reach you at different times from different directions due to different pressures, temperatures, mountains, etc. on the way.

But there would be a spot where the pressure waves would cross?

I think so. I think there is necessarily a circle "eversion" (turning it inside-out) with a crease. Whatever is the point of the crease would hear sound from all directions. Even with something like a figure 8 collapsing wavefront, eventually one or more creases should form.

Re: How big was the Tonga eruption?

#178

Post by lnwlebjel »

I posted a visualization of the shock wave as a submission, but I"ll repost it here. This is a satellite measurement of integrated atmospheric water vapor (IIUC), so changes in the density of air change the integrated measurement, such that you can see the shock wave travel around half the globe.

https://cimss.ssec.wisc.edu/satellite-blog/images/2022/01/22...

(it take a few seconds to load, but I believe this is one of the most incredible things I've ever seen).

Re: How big was the Tonga eruption?

#179

Post by dredmorbius »

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 (?)

I ran a quick bit of napkin maths a few days back here on HN.

Based on 6 MT energy release, a maximum of 11 million tonnes (or 11 million m^3) of water could have been vapourised.

Liquid-to-gas expansion is on the order of 1,000 times, not 70x. This would be 11 km^3 of expansion.

If the erruption yield was higher, and I've seen values of up to 50 MT suggested, the amounts would be roughly 9x greater: 100 million tonnes and 100 km^3 of steam.

All of this is very rough and is strictly based on the quantity of energy and the heat of vapourisation of water. Actual quantity of water/steam is likely lower. There's no geology involved in the estimate, just physics.

See: https://news.ycombinator.com/item?id=30019044

Re: How big was the Tonga eruption?

#180

Post by llampx »

dr_dshiv wrote: post #170

And it still wasn't big enough to put sufficient sulfur dioxide in the atmosphere to have a noticeable cooling effect. Too bad :( https://www.bbc.com/news/science-environment-60088413

Too bad? It would be extremely cool for one summer, ruining crops and causing famines and then back to hotter summers from next year onwards. How does that help anyone?
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