I was thinking at least a 5 myself but I was reading this which would suggest only 2 if I'm reading it correctly.

 

https://www.gdacs.org/report.aspx?eventtype=VO&eventid=1000036

 

Surely it's bigger than a 2.

It may be this eruption was violent but short lived, so it's total 'VEness' () smaller. It does look a little like the island has been blown up. But then Krakatoa was a similar situation?

This is exceptionally cool: 

Using a difference overlay, I can accentuate that shockwave as it traverses the entire globe. The antipode of Tonga is over Northern Africa. #tonga #HungaTongaHungaHaapai @NWS @USGSVolcanoes pic.twitter.com/BNS0DsfLrm

— science.out.there (@ScienceOutThere) January 15, 2022

 

It may be this eruption was violent but short lived, so it's total 'VEness' () smaller. It does look a little like the island has been blown up. But then Krakatoa was a similar situation?

It might reflect a relatively small amount of material - one theory for the eruption is an earthquake or initial explosion caused part of the island to slide in to the sea, which allowed sea water to mix with the revealed magma and that went 'bang'. In that scenario there'd be a lot of steam, some ash but maybe not much more than that? I guess it could also have been a similar thing with part of the volcano that's underwater. 

There's a really cool radar image of before and after the eruption on the BBC:-

Pacific volcano: Ash-covered Tonga is like a moonscape say residents - BBC News

I know a large part of the island was relatively new and made of ash etc. from earlier eruptions so not exactly durable but even so it looks to have essentially destroyed it.

That said a VEI2 does still seem a little low given how large the ash cloud was and how high in to the atmosphere it went

 

It might reflect a relatively small amount of material - one theory for the eruption is an earthquake or initial explosion caused part of the island to slide in to the sea, which allowed sea water to mix with the revealed magma and that went 'bang'. In that scenario there'd be a lot of steam, some ash but maybe not much more than that? I guess it could also have been a similar thing with part of the volcano that's underwater. 

There's a really cool radar image of before and after the eruption on the BBC:-

Pacific volcano: Ash-covered Tonga is like a moonscape say residents - BBC News

I know a large part of the island was relatively new and made of ash etc. from earlier eruptions so not exactly durable but even so it looks to have essentially destroyed it.

That said a VEI2 does still seem a little low given how large the ash cloud was and how high in to the atmosphere it went

 

 

The volcano is underwater and it's huge! Just parts of it stick out or at least they did. That huge ash cloud isn't a result of simple water & magma reacting but rather a deeper reserve of gas rich maga erupting. This eruption will have created a new caldera for sure. 

I think a strong VEI4 at the very least. 

This website has a detailed images of the volcano 

https://theconversation.com/why-the-volcanic-eruption-in-tonga-was-so-violent-and-what-to-expect-next-175035

I

 

It may be this eruption was violent but short lived, so it's total 'VEness' () smaller. It does look a little like the island has been blown up. But then Krakatoa was a similar situation?

But that sheer volume that was ejected into the atmosphere & spread hundreds of miles across in only a couple of hours, so perhaps more than what we might have thought possible has been ejected. Also it continued to erupt over night.

https://en.wikipedia.org/wiki/List_of_large_volcanic_eruptions_in_the_21st_century 

 

The volcano is underwater and it's huge! Just parts of it stick out or at least they did. That huge ash cloud isn't a result of simple water & magma reacting but rather a deeper reserve of gas rich maga erupting. This eruption will have created a new caldera for sure. 

I think a strong VEI4 at the very least. 

 

This website has a detailed images of the volcano 

 

https://theconversation.com/why-the-volcanic-eruption-in-tonga-was-so-violent-and-what-to-expect-next-175035

I

Ya, I get that. There's some interesting stats and images in that article too, as you say shows the scale of the volcano nicely. (Kind of reminds me of the Krakatoa crater with just small islands left above the sea).  

It'll be interesting to see what they decide the exact cause was over the coming days. The seawater being in the mix would have increased the explosivity of the eruption I think, given the type of eruptions that volcano produces (i.e it generally erupts explosively rather than a relatively slow fissure style eruption, so any interaction with water would have been lots of magma all at once and lots of water flashing to steam has to go somewhere). 

The partial collapse leading to violent eruption theory was on one of GeologyHubs videos on Youtube (No idea what qualifications the person has who makes those, they were suggesting it was likely to be a strong VEI4 from initial footage). 

Edit: changed the VEI comment as think that Wiki page has been updated to say strength unknown again?

Estimated VEI now shown as 5.
https://en.wikipedia.org/wiki/List_of_large_volcanic_eruptions_in_the_21st_century

There is nothing on that link that say's it's estimated VEI however on the 2022 eruption page there is a suggestion that it could be in the magnitude of a VEI 5. It is however still very early days and I've also read this is also the largest eruption in 30 years - Pinatubo was a VEI 6

Sulphur levels however appear to very low given the size of the eruption so not a climate altering eruption.

 

There is nothing on that link that say's it's estimated VEI however on the 2022 eruption page there is a suggestion that it could be in the magnitude of a VEI 5. It is however still very early days and I've also read this is also the largest eruption in 30 years - Pinatubo was a VEI 6

Apologies. It did, and then it didn't.

BBC's take on the eruption:

Pacific volcano: Science explains event's ferocity
https://www.bbc.co.uk/news/science-environment-60029815

Roger

Interesting seeing some of the data coming out now regarding the eruption, seems likely to have the highest number of lightning strikes of any eruption recorded. Admittedly that's limited to how long we've been able to accurately detect and record this but still impressive - I've seen figures of 200,000 + for 'the eruption' which I assume was just the 15th Jan event and 600,000 which I'd assume was including the December activity and earlier fairly large eruption on 14th Jan.  There's suggestions that the eruption column may have reached as high as 37km or so, which would again be the highest recorded although think that's TBC as there's contradictory info on that.

The global impacts are pretty astounding too, with at least one component of the Tsunami likely to be as a result of the pressure wave punching down on to the ocean - there's reports of 12cm or so waves affecting the Caribbean, which would pretty much have to have been caused by the pressure wave. It's also possible the explosive eruption itself caused or contributed, along with the possibility of a large amount of material sliding down in to the caldera or ocean floor. 

Judging by satellite pictures the 14th Jan event took out a large chunk of the newly formed bit of land between the 2 islands/caldera rim pieces and the 15th Jan looks to have taken out the remainder and a fair bit of the original islands. 

For the power of the eruption relatively small amounts of SO2 was emitted and the event itself was relatively brief, unusually so for an eruption of this size. As there's evidence from historic eruptions that the large explosive eruptions from the volcano tend to be a series of events it's possible further eruptions will occur, depending on just how much magma was expelled in this event. I guess how likely further eruptions are will be determined either by a more accurate quantification of the material ejected to compare with possible size of the magma chamber to get an idea of how much eruptive material is left, or by further eruptions occurring over the coming days. 

Clearly a tragic event for those affected, but one you can't help but find fascinating. 

Rather a shame that this being the BBC their journalist couldn't be bothered to do a little research before writing this.

"Early data suggests the Tonga event could have measured as high as five on the volcanic explosivity index (VEI). This would certainly make it the most powerful eruption since Pinatubo"

There have a been a number of VEI5 eruptions since pinatabu 

Tonga volcano: Eruption more powerful than atomic bomb, Nasa says

https://www.bbc.co.uk/news/world-asia-60106981

The last 2 nights have provided incredible sunsets here in Western Australia. The sulphur aerosol from the Tonga volcano in the Stratosphere is allowing the sky to be glowing over an hour after the sun has set. It’s truly spectacular and evidently the eruption column broke into the mesosphere at around 58km. An incredible event which now over a month later is giving us truly incredible sunsets. 

The Azores is currently giving concern. There’s been a lot of seismic activity there over the past week or so and they’re preparing for something bigger. The government has advised against all but essential travel to The Azores. 

I posted about seeing the La Palma volcano on a cruise in November.  We did another cruise last month and actually visited La Palma.  It’s a beautiful island and thankfully, the only sign of damage is a dusting of black ash everywhere.  When we saw the volcano, we were on a cruise that should have gone to The Azores but didn’t due to Covid, which was a bit disappointing as I’ve never been there, but it couldn’t be helped.  We’re supposed to be on a cruise next month which includes The Azores!  Hmmm!