Talk:Volcanic Explosivity Index

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Than you for fixing the page. 17:51, 15 February 2007 (UTC)Dave Someone really messed with this page it is nolonger suitable for the academic use I need. 19:01, 8 February 2007 (UTC)Dave Freeborn New Mexico Office of Emergency Management


Looking at both this article and the article on Vesuvius, it's difficult to imagine the 79 AD eruption (ostensibly a once-every-two-millenia event and a Plinian eruption) is not assigned a VEI in at least one of these articles.

Could someone who knows about this add a few major well-known eruptions to this page for perspective. For instance, Krakatoa, Mount St. Helens, Pinatubo, whatever. --rmhermen

Krakatoa was a 6, Mount St. Helens a 5.

I added some more "interesting" eruptions. However this list could get really big. I don't think this is the right page for this list. List of volcanoes is also not the right place since volcano and eruption are not the same (many volcanoes on the current list should be on it multiple times). I think there should be a new page list of volcanic eruptions. See also List_of_volcanic_eruption_deaths, Top_10_most_deadly_volcanic_eruptions. Maybe it should be list of largest volcanic eruptions. Jdorje 02:12, 21 May 2005 (UTC)
Honestly making a list by hand is probably not a good use of time. The global volcanism program already has a huge database of eruptions. Simply looking at this list of VEI 4+ eruptions [1] should be intimidating. Looking closely at the information for each eruption you'll see the amount of raw data they have is staggering. Jdorje 04:41, 12 July 2005 (UTC)
I agree that the eruption list is useless. As noted, the The Smithsonian Global Volcanism Program maintains a database of eruptions, constantly updated, for all volcanoes with eruptions in the last 10,000 years. Currently there are more than 9,500 known eruptions from over 1,500 volcanoes. Why try to reproduce any of that by hand when it will be out of date almost immediately? I won't delete it due to a "conflict of interest" though. GVP Webmaster 22:19, 26 December 2006 (UTC)
What about Cosiguina eruption (Nicaragua) of 1835 ? I think it should own a respectable VEI...(didn't it deposit ashes until Mexico/Jamaica/Colombia ?)
Trying to do a list before Holocene. List of large volcanic eruptions --Chris.urs-o (talk) 21:01, 23 March 2010 (UTC)
One reason for including the list is to try to educate readers who have heard of famous/infamous/notorious eruptions but don't have a sense of how big they were relative to one another or what else like them is in the historical record. The statement "the example of a VEI 6 eruption is Krakatoa, and here are the others like it" will inform a reader who's heard of Krakatoa but not Novarupta. That's good, IMO, but it does suggest using "trite" eruptions for each VEI level, and avoiding the ones that are atypical in one way or another. -- Bill-on-the-Hill (talk) 04:41, 8 June 2010 (UTC)

VEI 8[edit]

The table in this article states that there has been only one (known) vei 8. However, in the article about supervolcanos about 10 examples are given. Either I'm missing something or one of these articles is mistaken. S Sepp 16:19, Oct 29, 2004 (UTC)

I think what they mean there is that, in human history, only one VEI=8 event, Toba, is known to have occurred. --Golbez 04:12, Dec 29, 2004 (UTC)

What it means is in human lifetime the toba eruption is the only one to have occured. This is wrong Lake Taupo erupted 26,500 years ago erupting over 1,170km3 making it a super-euption also. Also 7 other vei 8 eruptions have happened in the last 30 million years but these were not in human lifetime. The others are stated as supermassive eruptions (VEI7) not super eruptions like Taupo or Toba.

1 and 2[edit]

Is the jump between 1 and 2 a mistake? The only authority I see for it is the USGS Glossary illustration which could easily be in error. No acknowledgement appears in the text, which is vague or even contradictory ("Each increase in number represents an increase around a factor of ten. The VEI uses several factors to assign a number", but "[in the figure] Each step increase represents a ten fold increase in the volume of erupted pyroclastic material"—except for #1!). Kwantus 01:24, 2005 Jan 5 (UTC)

Power Output[edit]

I know little about vulcanology (although I know more now:>), but from what I can determine, the power output of an eruption seems to be a significant measure of volcanic explosivity. The VEI classification does not consider this. I have preemptively added a statement on this issue in the article, but a section detailing the weaknesses of this classification might be better. Opinions?--ChrisJMoor 02:25, 12 Mar 2005

I agree, and have a couple of question. In physics, power is work over time and so is a scalar quantity. Isn't it superfluous to write "magnitude" of power. Why not just "the power output" or something?

At the beginning of the next section, it reads "Scientists indicate how powerful volcanic eruptions are using the VEI." In this section it reads "One weakness of the VEI is that it does not take into account the magnitude of power output of an eruption." Is this not a contradiction? Is there a difference between the "magnitude of power output of an eruption" and how powerful an eruption is? Aliotra (talk) 00:38, 27 March 2009 (UTC)


Several of the articles linked to or from this one mention explosive power in megatonnes. It would seem that adding a column to the table giving ranges would be very useful. Anyone know of such info? Maury 19:25, 10 Apr 2005 (UTC)

I have my doubts about the megatonnage calculation. I don't know the original source -- the 200 megaton number is replicated all over the Web.
I'm uncertain about these numbers. Consider Krakatoa. The amount of energy to lift 10 cubic kilometers of material with a density of 3 gm/cm^3 to a height of 25 km is about 7 x 10^18 J. A megaton of TNT is (somehow) calibrated to be 4.2 x 10^15 J. So, my rough computation is that Krakatoa would be 1600 megatons! Well, maybe not all of the material was lifted all the way to 25 km, but 200 megatons would imply it was lifted an average of 3 kilometers. Maybe we need to divide the plume height by 8, to get an average height?
I hope an expert on computing the energy of volcanic explosions will chime in. -- hike395 20:42, 10 Apr 2005 (UTC)
Making up numbers like that isn't a good idea since there are too many variables for us to take into account. However 7 x 10^18 doesn't seem that high; the 2004 Indian Ocean earthquake is estimated at 2.0×1018 joules. I'd agree that the measurement of energy would be the most accurate method of assessing a volcano's explosivity, but I have no idea how a volcanologist would go about calculating that. The Moment magnitude scale might be useful here - naively I would assume a VEI 6 volcano would be similar to a magnitude 9 earthquake. Jdorje 02:22, 21 May 2005 (UTC)
A mag 9 earthquake is realeases vastly more energy than a VEI 6 volcano. Estimates for the energy released in the last mag 9 quake (which caused the boxing day tsunami) run at about 4.0×10^22J.
Do not forget that an eruption also release a great amount of energy in the form of heat, and not only mechanical energy.

Problems with VEI[edit]

I'm no volcanoligist, but simply trying to explain and categorize existing volcanoes on Wikipedia shows up several major problems with the VEI system. (All numbers below are for the purposes of argument; most are from memory and may not be accurate.)

  • Quantization. While earthquakes are measured using a continuous system (to one or two decimal places) most volcanoes explosivity measurements have only one significant digit. This is a major problem when comparing volcanoes of near-equal explosivity that happen to fall on different sides of the boundary, or for very different volcanoes that happen to fall in the same category. For instance Tambora (80-150 km³) was a minimal VEI 7 volcano while Long Valley Caldera (750 km³) was a a very large VEI 7. This is also a problem when there is uncertainty about the eruption size. Consider Santorini (50-200 km³), Taupo (85 km³), and Tambora (80-150 km³). Should Taupo be a VEI 6 while the others are VEI 7, even though Taupo could have been the largest of them? Very rarely I've seen decimal places used in the literature (one source claimed Santorini was a 6.9), but almost all sources stick to integers (sometimes with caveats, like "6-7" or "6+").
  • Different measurement techniques. From what I've read, geologists looking at ancient eruptions usually measure in "dense rock equivalent". Thus Toba erupted material equivalent to dense rock of 2800 km³. By comparison modern eruptions are usually measured using whatever scale is handy. Pinatubo erupted 10 km³ and Mount Hudson 6 km³ of ash, but this would be the equivalent of only a small fraction that amount of dense rock. By comparison Laki released 14 km³ of lava (dense rock) and another 12km³ of tephra (mostly ash). Looking at the weight of the ejecta can help in comparisons here, but most sources don't include the weight. It seems obvious that the best solution here is to look at the amount of energy released in the eruption rather than in the amount of rock released (see "megatonnage" discussion).
  • Explosivity isn't a good indicator of effects. In many eruptions it's not the explosion itself that causes effects. Pinatubo, Hudson, El Chichon, and (presumably) Tambora and Toba's largest effects were from the release of sulphur dioxide, which may itself not have been at all explosive but had the largest global effects (in particular El Chichon was only a VEI 4 but had a larger global impact than any recent VEI 5 eruptions). This is true of earthquakes as well to some extent - location and type of the earthquake play a big role in how much devastation it causes, as the two recent Sumatran earthquakes have shown - but this isn't really the same thing since earthquakes don't have global or long-lasting impact.
Sulfur dioxide emissions by volcanoes.

I guess my conclusion would be that the VEI measurement is immature, much like the Richter scale measurement was before it. A more advanced measurement would probably give two numbers. An explosivity magnitude would be measured from the energy release of the eruption and could be calibrated either to use the moment magnitude scale or to correspond roughly to the current VEI system. Meanwhile the climate effect value would approximate the global climate effect by measuring the amount/effect of different climate-effecting gasses (SO2, NO2, CO2) that were released by the eruption (see sulfure dioxide figure, right).

Also, I wonder if the problems with the VEI system should be put into the article (the measurement techniques issue is already mentioned).

Jdorje 05:32, 12 July 2005 (UTC)

last-10000-years numbers[edit]

These numbers need some sort of disclaimer because they are known to be incomplete. There are 4 VEI7 eruptions, one every 2500 years - the last one happened to be just 200 years ago but this is coincidence. There are 43 VEI6+ eruptions, one every 250 years - but there have been 4 (Tambora, Krakatoa, Katmai, Pinatubo) in the last 200 years alone. Further down the list there have been 4000 VEI2 eruptions - one every 2.5 years - but these are listed as weekly occurrances. My point is just that many/most eruptions of the last 10000 years are not known, particularly for the smaller volcanoes. Someone looking at these numbers expecting to get something out of them will be rather mislead. Jdorje 16:00, 21 September 2005 (UTC)

Is it that evidence of VEI-6 can usually be found, VEI-5 if one looks close enough? For smaller eruptions I guess the number will always be inaccurate, as the evidence is destroyed in later eruptions. —Preceding unsigned comment added by (talk) 04:55, 23 September 2007 (UTC)

They are further inconsistent in other regards. Consider the VEI-2 claim of 3477 occurences. This amounts to roughly thrice a year, but the frequency is given as "weekly".

(In addition, using the 1994 number with that many significant digits today is misleading.) (talk) 19:13, 18 May 2009 (UTC)

VEI literally mean "volcanic Explosive Index" and title is in PAST TENSE. This time-frequency of explosions is referring to "present or future repeation". therefore that column should be removed. (talk) 04:46, 23 September 2013 (UTC)

km³ versus m³[edit]

someone was asking about these comparisons...1 km³ = (1000 m)³ = 109 m³ = 1 billion m³. — jdorje (talk) 17:52, 9 February 2006 (UTC)

The Fish Canyon Tuff (La Garita Caldera) was not a VEI-9 eruption[edit]

Someone has stated that the Fish Canyon Tuff from La Garita Caldera was a VEI-9 eruption and that the volume was 18,000 cubic km. Both are inaccurate. Nowhere in the article [2] does it state that the FC Tuff had a high volume as this. In fact, it's still stated as 5,000 cubic km in that article by Mason et al. [3]. Because the volume erupted is less than 10,000 cubic km, it is still a VEI-8 eruption. If you read the article carefully (see first link in this paragraph), you will notice that "Magnitude" is really a separate scale, and it is important to note that VEI and magnitude measure eruption sizes differently. VEI measures eruption sizes based on volume of magma erupted in cubic km and eruption column height. Magnitude, as used in the article by Mason et al, measures eruption size based on mass of magma erupted in kilograms. NorthernFire 06:10, 26 July 2006 (UTC)

Sorry, that was me. I misread the article. Thanks for fixing my mistake. -- Avenue 08:58, 27 July 2006 (UTC)

There is a valid reason why VEI only attains 8. Anything larger would require the whole Earth. Incidentally someone raised the point why the VEI uses only whole numbers. It doesn't it uses tenths hence a VEI 7.1 is larger than a VEI 7 but only just. The VEI is a measure of just how large an eruption was and like most indicators is subjective to interpretation. Two volcanologists might assign different values to an eruption, but eventually a consensus will be reached. Incidentally if someone wants to link Stephen Self properly to the lead item they might like to try connecting to Stephen Self Volcanology.The Geologist (talk) 13:24, 9 April 2012 (UTC)

Date of Taupo eruption (holocene)[edit]

Now what is the exact date of the Taupo eruption, that supposedly caused red sunsets in Rome? I've seen anything from 177 to 186 AD thus far. So what is the latest? I think 177 is, dated via Greenland ice-cores by Zielinski (Science 264 [1994], p. 948f.). I am right? --Bender235 20:14, 13 December 2006 (UTC)

Flood Basalt vs. Tephra[edit]

It seems that some Flood Basalt events have been added with very large VEI numbers due to the volume of the products. But the definition at the top of this VEI article says that VEI is based on the volume of Tephra. To the best of my understanding, Tephra is airborne matter whereas a Flood Basalt is floods like a liquid.

So is the definition of VEI wrong in this article, is it an error to include Flood Basalts in the table, or is my understanding in error? -- Cjensen 02:54, 17 January 2007 (UTC)

  • It is probably an error to include flood basalts in the manner it was done in this article, thus I've removed the VEI-9-11 info in both tables in the article. Also, the uppermost limit of the VET is apparently 8 according the the Smithsonian Global Volcanism Program (Smithsonian GVP) - there doesn't seem to be any such thing as a VEI 9 or higher. You are correct in that tephra is airborne pulverized volcanic rock. It's really another name for volcanic ash. The VEI is not without its flaws, and I believe they take into account more for explosive eruptions of tephra. Take for example the Eldgjá fissure eruption in Iceland in the year 934 CE. It erupted over 18 km2 of basaltic lavaa - the largest known eruption of lava in historical times, yet Eldgjá erupted only 4 km2, so it mostly effusive/mildly explosive in nature and was assigned a VEI of 5. In comparison, Krakatoa was over 20km2, made mainly of tephra and was assinged a VEI of 6. Speaking of flood basalts, a flood basalt does not just form from a single huge individual eruption of lava. Rather, a flood basalt is made up of hundreds or thousands of individual eruptions of fissure-fed lava flows over a period of several million years, and they would have been mostly effusive, although there is evidence for some fairly large steam-generated eruptions in flood basalts perhaps prior to the actual fountaining of lava as the magma hit groundwater. But many of those individual eruptions of lava in a flood basalt can still be quite huge, generally anywhere from 100 km2 to over 2,000 km2 - about the same volume range for large caldera-forming eruptions like Yellowstone 640,000 years ago. The only difference is the kind of magma that comes out. NorthernFire 22:19, 21 January 2007 (UTC)

I Agree maybe a new system is needed so that it judges both tephra and basalt eruptions. Wiki236 14:19 25 January 2007 (UTC)

Looking at Grímsvötn it looks like a basalt flow eruption in 1783-1785, but a tephra eruption in 8230 BCE ± 50 - both look to have been described as VEI 6. However basalt flow doesn't seem explosive to me - perhaps one of those eruptions should have a different VEI listing? EdwardLane (talk) 10:44, 23 May 2011 (UTC)

As I understand it VEI is just described based on total tephra, with basalt volumes only being being included under Dense rock equivalent so it should be possible to look at the VEI and the DRE of an eruption - and take the proportion of DRE that is included in VEI to give some characteristic of the effusive/explosive nature of the eruption - with DRE giving some idea of scale. Interesting that VEI has the volume required to rate volcano in order of magnitude or tephra but the DRE article does not have the equivalent DREindex. EdwardLane (talk) 10:30, 7 June 2011 (UTC)

Tenerife [edit]

Does anyone know if the Caldera on the Island of Tenerife (Las Cañadas) is a supervolcano or not?. All I know is that it was most likely created in a VEI 7 explosion 150,000 years ago, could anyone help me out? Wiki235 18:15 31 January 2007

No, it was not. See supervolcano. Guanlongwucaii (talk) 09:46, 27 May 2009 (UTC)Guanlongwucaii

As a geologist / volcanologist working and living on Tenerife, I can assure you that the Las Canadas caldera was not formed in an eruption 150 ka, but as a series of edifice failures - these being the Ucanca caldera (oldest), Guajara caldera (younger) and the Diego Hernandez about 150 ka. El Teide is the Las Canadas IV volcano. There are several papers and books dealing with the formation of the Las Canadas caldera. There are various physical reasons why the caldera was not formed in one cataclysmic eruption. The estimate of the VEI is about 5 for all eruptions of the Las Canadas volcanoes. By the way does anyone know how to add accents? as the "N" in Canadas should have an accent like a tilde over it. Thanks.The Geologist (talk) 13:33, 9 April 2012 (UTC)

Discontinuity between VEI 0 and 1[edit]

This topic had already been mentioned some time ago, and maybe a solution has been found meanwhile (but not mentioned in the article). There is a discontinuity in the amount of ejecta that increases by a factor of 100 between VEI 0 and 1, but by a factor of 10 in the rest of the table. Apparently, this table (and probably most of, if not all other VEI-related web sites) is based on this USGS page. As can be seen there, this discontinuity could easily be caused ba a simple misprint in the labels within the diagram since it is never mentioned elsewhere. If this discontinuity is a feature, what is the reason for it? Since this discontinuity is obvious, it should be mentioned in the article (at least the fact, that the reason is unknown).--SiriusB 08:51, 29 May 2007 (UTC)

The original paper proposing the scale (Newhall and Self, 1982) is cited in both our article and the USGS page you linked. It would probably be the best place to look for a reason for the discontinuity. I agree it would be useful to at least note the jump in our article. -- Avenue 14:22, 29 May 2007 (UTC)
Unfortunately, I have no access to this paper (probably there is no scanned version online according to the ADS). If anybody has access to it via a library of a geological institute or so, it would be nice if he or she could have a look into it. Meanwhily the USGS page appears to be the only public source, and therefore the possibility of a simple misprint in the figure (as fas as I can see it is the only source for all public available data including this WP article) is not ruled out.--SiriusB 12:41, 5 June 2007 (UTC)
It is not the only online source. For example, the tables in this definition from the Smithsonian Institution give the same cutoff, twice. I don't think the suggestion that it's an error has any credibility, and I've deleted it from the article. -- Avenue 03:22, 6 June 2007 (UTC)
However, I cannot see any explanation for this discontinuity, and unless one of us gets access to the Newhall C G, and Self S (1982) paper (which seems to be the origin of the table) we cannot rule out the possibility of an error (errors of this kind happen much more often even in fully refereed papers than most people think). I think that this discontinuity is so striking that an error seems to be more probable than a real feature (that otherwise would have been discussed somewhere). On the other hand, if it is intentional then it casts doubts on the usefulness of such a definition of the VEI unless explained plausibly (not only in a non-free paper but also on the public web pages). Therefore I suggest to mention this possibility in the article.--SiriusB 17:21, 7 June 2007 (UTC)
Personally, it doesn't surprise me that smaller eruptions would be treated differently by the scale, but that is not the issue. Discussing your personal speculations about possible scale errors in our article is not appropriate. Please do not add them unless you can provide an external source mentioning at least the possibility of an error. -- Avenue 22:29, 7 June 2007 (UTC)
Unfortunately, the Newhall/Self 1982 article is not available online (even to university subscribers), so I'll just go and photocopy it from the library tonight. But I think it's likely that the factor of 100 was done intentionally so that VEI 0 would contain only non-explosive eruptions. Incidentally, I think the table at Volcanic Explosivity Index#Classification may have an error, in that the VEI 0 ejecta volume should say "<10,000 m³" instead of ">1,000 m³". This is what both USGS and GVP imply. But I'll wait to make any changes until after reading the original paper. --Seattle Skier (talk) 22:49, 7 June 2007 (UTC)

Well, I photocopied the Newhall/Self 1982 article (BTW, the reference to it was wrong, now fixed), and I have read through it twice. The VEI scale is now correctly presented in the article: VEI 0 is < 10,000 m³, while VEI 1 is between 10,000 m³ and 1,000,000 m³. The paper provides no explanation for this, but the authors spend much time and effort discussing the approximate nature of the scale and the difficulty of categorizing eruptions below VEI 2. So it appears likely that this extra order of magnitude was done simply to ensure that truly non-explosive eruptions would fall definitely into VEI 0, while the extra-broad VEI 1 classification could accomodate all borderline exposive eruptions (that's my own opinion based on reading the paper). I don't think there's any legal way to post the Newhall/Self 1982 article online, so others will have to track it down in their local university library and draw their own conclusions, if they wish to do so. --Seattle Skier (talk) 06:46, 8 June 2007 (UTC)

The Newhall and Self paper is available at this address: Newhall, Christopher G.; Self, Stephen (1982). "The Volcanic Explosivity Index (VEI): An Estimate of Explosive Magnitude for Historical Volcanism" (PDF). Journal of Geophysical Research 87 (C2): 1231–1238. Bibcode:1982JGR....87.1231N. doi:10.1029/JC087iC02p01231. Yes it does work if you go back to the article and click on it in "References."The Geologist (talk) 16:46, 21 December 2013 (UTC)


Shouldn't the article mention VEI-9? 05:28, 13 August 2007 (UTC)

No. There is no 9 on the scale. — jdorje (talk) 23:04, 25 September 2007 (UTC)
Yes. The scale is theoretically open-ended, just because there haven't been any confirmed VEI-9 eruptions on Earth so far doesn't mean that there won't be in the future. Newhall and Self (1982) (talk) 21:07, 31 October 2008 (UTC)
Huh? La Garita is VEI 9.3 (see source). ~AH1(TCU) 19:54, 8 November 2008 (UTC)
I think I know where you're getting the "VEI 9.3" from. You stated that you mentionend a couple of sources stating such a magnitude, but what happened was that a couple of years ago, I did come across what was probably one of the scientific papers you mentioned. I remember that it was apparent that whoever wrote the paper was using a different scaling system to measure the scale of volcanic eruptions, even though the VEI was mentioned. Their own scaling system was taking into account the mass erupted in kg - something that the VEI doesn't appear take into account. I mentioned the discrepancy in the La Garita article's discussion page at that time as well. I do, however, have to agree that the VEI scale as used by the Smithsonian Global Volcanism Program (GVP) is in theory open-ended, even though goes only up to 8 (see the following link: A VEI of 8 would denote a volume of at least 1,000 cu. km. The next step up (VEI-9) would be over 10,000 cu. km, because the VEI is a logarithmic scale in terms of volume erupted. But, while La Garita Caldera is the largest known eruption to have occurred on the face of the planet, the largest individual eruption (Fish Canyon Tuff, about 27.8 million yrs ago) is not known to exceed ~5,000-6,000 cubic km. There are no known eruptions which have occurred on this planet to have erupted a magma volume of over 10,000 cubic km - yet. As huge an eruption it was, La Garita would still be in the VEI-8 range. NorthernFire (talk) 23:09, 8 November 2008 (UTC)
Having read the source that supposedly supports La Garita being "VEI 9.3" I can assure you that that term is used nowhere in the paper. The source discusses 47 VEI 8 erruptions including La Garita and assesses them against a magnitude scale of their own device which is not the VEI scale for which they use the letter M. --LiamE (talk) 06:31, 16 November 2008 (UTC)
I have read the article too and agree with number 5 [LiamE's comment - the numbers are now removed]. there is no mention. it is also not an open ended scale. 20:39, 23 March 2010
Quote: "The open-ended VEI scale applies only to explosive eruptions, with the VEI value determined primarily by the volume of eruptive products, height of the eruption cloud, and eruption duration, but with qualitative observations of explosivity (e.g., “gentle,” “cataclysmic,” “colossal”) also considered." Tilling, R. I. (14 December 2009). "Volcanism and associated hazards: the Andean perspective" (PDF). Advances in Geosciences (22): 125–137. Retrieved 2010-03-16.  --Chris.urs-o (talk) 20:51, 23 March 2010 (UTC)

Eruption count[edit]

According to the cited Global Volcanism Program page, no VEI-8 or "super-eruption" has occured in the past 10,000 years (which the table says it lists when it give 1 for VEI-8). The most recent eruption of that size was the Lake Taupo event around the end of the Last Ice Age 26,000 years ago. I think that whole erution count given for each category may need to be reassessed. -- §HurricaneERICarchive 03:00, 23 December 2007 (UTC)


Hasn't Thera(Santorini) been reconsidered as a VEI 7 volcano?.

--Triou —Preceding unsigned comment added by Triou (talkcontribs) 23:00, 20 March 2008 (UTC)

Isn't that still a bit uncertain? The Smithsonian database says the Minoan eruption was "7?" on the VEI scale; this site reports it as 6.9. I'd be happy to see sources that confirm it. -- Avenue (talk) 13:08, 21 March 2008 (UTC)
The highest estimations for the Minoan eruption are 70 km3 tephra, which is still VEI-6 (a large one, tho). However, 30 km3 tephra is more likely. --Bender235 (talk) 19:31, 24 April 2008 (UTC)

VEI 9 and 10[edit]

Since the VEI is actually "open end", we might add a 9 and 10 on the scale, since there have been eruptions of the magnitude: Deccan Traps (VEI 9), Emeishan Traps (VEI 9) and Siberian Traps (VEI 10). ––Bender235 (talk) 19:31, 24 April 2008 (UTC)

None of those were formed in a single explosive eruption, so the VEI doesn't apply. -- Avenue (talk) 01:23, 25 April 2008 (UTC)
Even if they did form in a single eruption, none of those eruptions appear to be explosive; they're flood basalts. Black Tusk 01:40, 30 April 2008 (UTC)

Before saying should "we" add effusive eruptions such as the Deccan Traps and Siberian Traps "you" need to consider what the term "VEI" means. There is a BIG clue as to why effusive eruptions are NOT included the term VEI stands for "Volcanic EXPLOSIVE Index." Effusive eruptions are by definition NOT explosive, even if they erupt fire fountains of lava.The Geologist (talk) 16:51, 21 December 2013 (UTC)

Classification table[edit]

If VEI is defined by volume of ejecta could we move that column left to be column 2 ? Rod57 (talk) 22:00, 27 November 2008 (UTC)

Thanks, that's a good idea. I've done it. -- Avenue (talk) 11:31, 26 May 2009 (UTC)

Something wrong with display units in figure[edit]

The figure describing VEI displays volumes with units of area, yet when you click on the diagram the enlarged diagram shows the correct volume units. RStillwater (talk) 15:14, 8 December 2008 (UTC)

I see what you mean. If you look closely, the superscripts don't quite look like twos either - they are actually threes that were being shrunk so small that they looked more like twos than threes. This problem seems to have arisen when someone converted it to vector format in April 2008; the original used a larger font size for the threes. I've done the same, and tidied up some other minor problems. It could still use some revision to make it less US-centric, though. -- Avenue (talk) 11:12, 26 May 2009 (UTC)

Non-Earth comparisons?[edit]

Would there be any value in including examples of directly-measured or estimated volcanic explosions from elsewhere in the solar system, e.g. Io or Mars, to illustrate the magnitude of eruptions there, as compared to on Earth? Io_(moon)#Volcanism Careful With That Axe, Eugene (talk) 15:58, 5 May 2009 (UTC)

Soufriere Hills[edit]

It is not a VEI 4 - See

Guanlongwucaii (talk) 09:46, 27 May 2009 (UTC)Guanlongwucaii

Deletion discussion of Category:Volcanoes_by_Volcanic_Explosivity_Index[edit]

Editors interested in Volcanic Explosivity Index may be interested in contributing at Wikipedia:Categories_for_discussion/Log/2010_April_22#Category:Volcanoes_by_Volcanic_Explosivity_Index. --SmokeyJoe (talk) 01:24, 22 April 2010 (UTC)

Use of Ma[edit]

Ma is presumably Mega Annum or a million years. If this is correct then the units should be shown as Ma BP. Any views? treesmill (talk) 13:53, 12 May 2010 (UTC)

"ago may not always be mentioned; if the quantity is specified while not explicitly discussing a duration, one can assume that "ago" is implied; the alternative but deprecated "mya" unit includes "ago" explicitly" Annum#SI prefix multipliers, wiktionary:annum, the references do not use ago at all, sorry. --Chris.urs-o (talk) 14:19, 12 May 2010 (UTC)


If I'm right. Europe's air traffic was disrupted by a VEI 2 eruption. Ok. The article states VEI 4, but the VEI is not fixed yet !!! Quote: "A firm number won't be assigned for some time, but so far, about 110 million cubic meters of tephra have been ejected during this eruption, and the plume has gone about nine kilometers into the air, so that’s a VEI of 4." (Hendry, Erica R. "What We Know From the Icelandic Volcano". Smithsonian (magazine). Retrieved 22 April 2010.  Check date values in: |access-date= (help)) --Chris.urs-o (talk) 06:55, 11 June 2010 (UTC)

I've also heard VEI 2, and in any case that eruption was clearly not a hugely powerful one - something the media largely failed to bring out, because the circumstances and the effects on air travel were so unusual. Most volcanoes do not produce ash with that kind of insidious effect on jet engines even when the ash is spread out in low concentrations - that was what happened with E-jökull, and it's dependent on the local geological circumstances.
And of course, the eruption didn't have that great explosive power - nothing like Mount Pelée, which is classed together with it here on level 4. Pelée was infinitely more violent. Now, the VEI index doesn't account for the force of the eruption in its peak stage, or for the amount of heat generated (which is linked to the explosive force), only for the volume of tephra blown out. I still think 4 sounds too high, and this should be checked with other assessments - the Smithsonian Project is not God, and some of their assessments are educated guesses.Strausszek (talk) 00:08, 14 September 2011 (UTC)

The reason that the Eyjafjallajökull was assigned a VEI 4 is simple. It started life as a strombolian eruption, but the melt waters from the glacier fragmented the lava and increased the amount of tephra flung into the sky. It was essentially a strombolian eruption which underwent a phreatomagmatic stage bordering on the vulcanian.The Geologist (talk) 16:55, 21 December 2013 (UTC)

some interesting stuff?[edit]

This [4] looks like it has some extra info that could be used to expand the VEI article. EdwardLane (talk) 10:44, 7 June 2011 (UTC)

Go ahead an be bold. By the way, don't mark your Talk Page edits as 'minor' as other user's watch pages often ignore minor edits. Careful With That Axe, Eugene Hello... 11:45, 8 June 2011 (UTC)
Thanks - I might get around to being bold (I don't generally have a problem with that) but I'm not sure I'm expert enough, but I'm gradually getting my head around the specifics of vei, this and the original comment got a 'minor' tag as it wasn't anything bold - perhaps I need to reassess when to tag as minor. Thanks EdwardLane (talk) 11:46, 9 June 2011 (UTC)

VEI 8 every 10.000 years?[edit]

Hey, I was looking at the table and it says that VEI8 eruptions happen every 10.000 years, however another article states that these events happen every 50.000 - 100.000 years.

Also, isn't there a VEI9? — Preceding unsigned comment added by (talk) 02:21, 1 January 2012 (UTC)

As far as we know, there is no currently discovered deposit of material that allows for a VEI 9 eruption. Even though it's perfectly rational that a VEI 9 eruption may happen, until one does or evidence of one is found, we can't add it to the article unfortunately.

As for the original question, if the evidence used for the articles are different, then the estimations of time-scales between events may be different. The second estimation would seem more correct, if we consider the last VEI 8 event known to have occurred, was Lake Taupo's Oruanui Eruption 26,500 years ago. Before that, it was the YTT approximately 74,000 years ago. This is roughly a time-scale of 50,000 years between these kind of events and thus it would more likely that the second estimation is correct.

However, more evidence than this will be needed because, of course, at some points in the geological record, there will have been much bigger gaps between VEI 8 events and at some points, much smaller gaps between events, maybe even a few thousand years. What people fail to understand about volcanoes and in particular these types of events, is that they aren't working on a timer, or a schedule. They will erupt when the conditions that allow them to are present, and this may not work in a cycle, despite what the media may tell you. It may be 1 million years before the next VEI 8 event occurs, or it may happen in the next 10 seconds. The fact is, a volcano will erupt when there is enough magma and a fracture route exists between the magma and the surface. Sometimes these conditions form in cycle-like periods of time and at other times not. In any case if you can find a scientific article or journal to provide the solid evidence needed to back your hypothesis up, then by all means change the article. Wiki235 (talk) 17:55, 5 April 2012 (UTC)

English prospectus and the Italian one does not match[edit]

English prospectus and the Italian one does not match. Mormegil (talk) 16:49, 23 June 2013 (UTC)

Date of Taupo[edit]

The VEI table says 24.5k years ago. The paragraph immediately underneath says the most recent VEI 8 eruption was Taupo 26.5k years ago (which corresponds with the actual eruption page). I'm assuming it should be 26.5k but any thoughts? — Preceding unsigned comment added by (talk) 12:31, 19 March 2014 (UTC)

A difference of 2,000 years usually indicates some confusion between BC and BP. Our table says 24,500 BP, which is consistent with the date of 26,500 years ago mentioned in the text, so that all seems okay. The Toba date seems a bit more suspect: the table says 74,000 BC, but the linked article says 73000±4000 years BP. At least the inconsistency is smaller than the error range quoted. --Avenue (talk) 10:58, 20 March 2014 (UTC)

Requested move[edit]

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: no consensus. Jenks24 (talk) 10:22, 10 June 2014 (UTC)

Volcanic Explosivity IndexVolcanic explosivity index – Not a proper name; the cited sources (other than the deadlink one) use lower case, as do many others. --Relisted. Armbrust The Homunculus 13:56, 27 May 2014 (UTC) Dicklyon (talk) 01:56, 20 May 2014 (UTC)

  • Disagree - the USGS glossary link (under 'External links') has initial caps in its definition. Although the link to the Smithsonian's GVP site's VEI definition page is now a deadlink - it seems that it wasn't reinstated after the website was substantially rebuilt some time ago (despite my later request to them, as a WP editor!) - the GVP website still uses initial caps, e.g. see under the "Eruptive History" tab for individual volcanoes in their online database. Cheers, Bahudhara (talk) 03:03, 20 May 2014 (UTC)
The glossary heading is in title case, but the same page has it lower case later. Dicklyon (talk) 04:14, 22 May 2014 (UTC)
There are many consumer price indices, e.g. they can be compiled for each country, state, even city, or for different time periods - however, there is only one VEI - it is unique. Cheers, Bahudhara (talk) 08:17, 1 June 2014 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.


I see someone moved the title of this article from Volcanic Explosivity Index to volcanic explosivity index awhile back, which in my opinion is incorrect. A quick google search shows that the VEI is normally capitalized. I suggest the article title be moved back to its original form. Volcanoguy 07:22, 28 April 2016 (UTC)

The subject of this article (Volcanic explosivity index) is the Volcanic Explosivity Index. There is only one index with this name. I'm not an expert in English grammar but I think this index is a proper noun, more strictly a proper name, similar to e.g. North America (which we do not write as North america). I think all three words of Volcanic Explosivity Index should start with a capital/uppercase letter.
Some of the sources that give initial capital/uppercase letters to all three words in the name of the Volcano Explosivity Index:
  • the creators of the index (Newhall and Self, 1982)
  • the US Geological Survey
  • the Smithsonian Institution's Global Volcanism Program
  • the Geological Society of London's Working Group on Super-eruptions
  • Oregon State University's Volcano World website
A volcanic eruption is given a specific index value (VEI 0 to 8) from the Volcanic Explosivity Index. Unfortunately and confusingly, this assigned value is called its volcanic explosivity index but this specific number is only a volcanic explosivity index, which I think is a common noun and this should be entirely in lower case.
I recommend that this article should be renamed to "Volcanic Explosivity Index" with a redirect from "Volcanic explosivity index". GeoWriter (talk) 15:17, 24 August 2016 (UTC)
  • Strong support - see my argument in the 2014 discussion above. Bahudhara (talk) 23:57, 24 August 2016 (UTC)
Even though it was pointed out in that discussion that your argument there was incorrect? Dicklyon (talk) 07:18, 4 January 2017 (UTC)

Requested move 4 January 2017[edit]

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

Not moved. There is a clear absence of consensus, and no realistic prospect for this to change in any further period of discussion. The evidence that the term is properly capitalized, while not dispositive of the issue, is reasonable to support the position of those opposed to the move. bd2412 T 20:33, 11 January 2017 (UTC)

Volcanic Explosivity IndexVolcanic explosivity index – Better sources (many or most books, and the original defining paper) use lowercase, treating this as a generic. Prior claims that the 1982 source capped it are seen to be false if one looks beyond title, headings, and abstract; in the text they say "The volcanic explosivity index (VEl) is a general indicator of the explosive character of an eruption." Per WP:NCCAPS and MOS:CAPS, let's reserve caps for proper names. Dicklyon (talk) 07:05, 4 January 2017 (UTC)

  • Support as nom, though I must apologize that when I had it moved by a technical request a while back I had forgotten about my previous RM that was thinly supported and closed with no consensus. I hope we can get more people to see it this time, and actually look at better sources such as books, and acknowledge that about half of all books use lowercase. A "quick Google search" is a poor substitute, since Google tends to rank headings and titles and things that look like them higher. Please do note that the original authors used it lowercase in the cited and linked 1982 paper, unlike what GeoWriter asserts above. And when I last checked (2014), all of the other linked sources also used lowercase. It's not clear why this proposal didn't just pass. Since then, the linked glossary seems to have been updated, too, since the term no longer appears there. This glossary was the basis for the one objection last time. Dicklyon (talk) 07:10, 4 January 2017 (UTC)
  • Oppose the original paper refers to it in caps in the abstract [5], and lowercase in the main text. Our sources in this article mostly refers to it in caps [6][7][8], as does the USGS see [9]. We have one source [10] that uses lowercase. It seems to me that the caps are warranted. Headbomb {talk / contribs / physics / books} 10:48, 4 January 2017 (UTC)
Headbomb, other than the 1982 abstract, none of the sources you link ever use the term in a sentence except where defining the acronym, so provide no evidence on whether they would consider it a proper name or not. One does use it lowercase in a ref title, which could signify that they think it is not. Dicklyon (talk) 18:34, 4 January 2017 (UTC)
Then you haven't read the sources, because they do. Headbomb {talk / contribs / physics / books} 21:42, 4 January 2017 (UTC)
It's possible that I missed something, since I scanned and searched, but didn't read them in their entirety. Can you point out what I missed? Dicklyon (talk) 21:51, 4 January 2017 (UTC)
I've rechecked all of them; in every case the caps are associated with the acronym defining only. Dicklyon (talk) 22:02, 4 January 2017 (UTC)
Dicklyon wrote "Better sources (many or most books)". Please clarify what you mean by "better". "Most books" - are you claiming that most geology books written since 1982 use lower case for the term under discussion? How many books is that exactly and have you checked them all? GeoWriter (talk) 14:12, 4 January 2017 (UTC)
"Better" sources are what you're likely to find with book search or scholar search, as opposed to web search. A quick scan of hits shows about half lowercase, and many of the uppercase ones are in titles, headings, and defining the acronym, so provide no evidence of whether they are considering the term to be a proper. I didn't read or count them all, as it's already very evident that they don't meet the MOS:CAPS criterion of "consistently capitalized in sources". Dicklyon (talk) 18:27, 4 January 2017 (UTC)
Dicklyon wrote "note that the original authors used it lowercase in the cited and linked 1982 paper, unlike what GeoWriter asserts above." What I asserted above (on 24 August 2016) was that Newhall and Self in their 1982 paper "give initial capital/uppercase letters to all three words in the name of the Volcano Explosivity Index". To show that I am not making anything up, here is a quotation from the Newhall and Self 1982 paper: "A composite estimate of the magnitude of past explosive eruptions, termed the Volcanic Explosivity Index (VEI), is proposed..." GeoWriter (talk) 14:43, 4 January 2017 (UTC)
Yes, as I pointed out in the move rationale, you need to look "beyond title, headings, and abstract" to see that the original authors use it lowercase in the text. That is, they do not consider their newly proposed term to be a proper name. Dicklyon (talk) 18:27, 4 January 2017 (UTC)
Unfortunately, Newhall and Self use both "Volcanic Explosivity Index" and "volcanic explosivity index" in their 1982 article. If only they had been consistent one way or the other, we would probably not now be troubled by this issue! I see no evidence within the Newhall and Self 1982 article to support Dicklyon's claim that the authors' upper case version (which appears not only in the article title but also in a block of article text) is invalid and should therefore be disregarded, yet the authors' lower case version is somehow allegedly correct, apparently based only on Dicklyon's opinion that the authors "do not consider their newly proposed term to be a proper name". It is up to Dicklyon to provide proof rather than opinion that the authors did not write, did not approve and did not give equal significance to the upper case spelling. The fact that the authors used both upper and lower case versions of the term suggests to me that a more likely explanation may be that their understanding of what is and isn't a proper noun was less than perfect and/or they didn't care enough. It's probably a salutary lesson to scientists on the pitfalls of defining new terms. I expect other sources are likely to use either upper case or lower case, not both. Ironically, should the original spellings in Newhall and Self 1982 now even be considered an unreliable source for the spelling in this Wikipedia article, because it seems to actually be the least definitive spelling source? GeoWriter (talk) 20:46, 4 January 2017 (UTC)
I would never suggest that someone else's style is "invalid" or should be "disregarded". Just that we should follow wikipedia style, per MOS:CAPS and WP:NCCAPS. Dicklyon (talk) 20:57, 4 January 2017 (UTC)
Yes other sources also do it different ways. This book uses ALLCAPs for defining the acronym, Title Case in the original article title, lowercase otherwise. This book uses Title Case for defining the acronym, lowercase in the title of the original paper. This book has it many times lowercase and a few Title Case. And so forth. Generally speaking the caps are either for the paper title, a section title or heading, or with the acronym definition – this is One Conventional Stye (OCS) but Not Ours (NO). A few sources do use Title Case when using the term in sentences; but not very many (e.g. a clear minority of those with "Volcanic Explosivity Index is"). Dicklyon (talk) 21:25, 4 January 2017 (UTC)
  • Oppose. Volcanic Explosivity Index is a proper noun. Volcanoguy 14:30, 4 January 2017 (UTC)
  • Oppose. Just because most sources clarify with (VEI) afterwards does not negate the capitalization. They could have written volcanic explosivity index (VEI) just as easily. It seems to be treated with all caps in most book and news sources; we should follow suit. --В²C 00:32, 5 January 2017 (UTC)
Some styles suggest capitalizing when defining acronyms, as "If you are going to acronym it, then capitalize it to indicate which letters form the acronym." And though most style guides suggest the opposite, the practice is very common. That doesn't mean it can't be a proper name, but that seems like the logical interpretation when uses not defining an acronym are overwhelmingly lowercase, as they are for this one. Dicklyon (talk) 00:52, 5 January 2017 (UTC)
I'm not seeing that. The usage in Gizmodo[11], this book on Climatology [12], etc., is typical of what I see. . --В²C 01:05, 5 January 2017 (UTC)
I'm also calling WP:IAR on any style guidelines that call for sentence case for titles that are names of things. I agree with sentence case for descriptive titles, as in Democratic Party presidential primaries, but when the title is the name of the article's topic,as is the case here, I think title case makes sense. --В²C 02:47, 5 January 2017 (UTC)
We have a pretty long tradition of only capping proper names, per WP:NCCAPS. If you want to change that, you'll probably need to propose it at a more central venue, not just ignore it here because you suddenly have a better idea. Dicklyon (talk) 03:40, 5 January 2017 (UTC)
  • Support. The major style guides in the US and the UK say to minimise capitalisation. Our own MOS says that the capping of initialisms is not a good reason to cap the initials when the item is expanded. We have countless examples of "index" on WP that are not upcased. Like this. Explicitly, our guidelines say not to upcase laws, hypotheses, rules, theories, etc. User:Volcanoguy, please explain what you understand "a proper noun" to be? Tony (talk) 01:08, 5 January 2017 (UTC)
According to a dictionary, a proper noun is a noun that is used to denote a particular person, place or thing. There is only one index with this name and I can tell you from years of research that the Volcanic Explosivity Index is generally capitalized. Volcanoguy 14:20, 5 January 2017 (UTC)
User:Tony, your link is to Diversity index, i.e. a diversity index, of which there are many, so I think it is not a proper noun. There is only one Volcanic Explosivity Index, i.e. the Volcanic Explosivity Index, which I think is a proper noun. GeoWriter (talk) 14:45, 5 January 2017 (UTC)
  • Support per WP:NCCAPS, MOS:CAPS. The fact that some sources capitalize it is irrelevant; unless virtually all of them do so consistently, WP uses lower case. There's nothing magically special about this topic that makes it an exception to the "when in doubt, do not capitalize" rule. The opposer's rationale, "the original paper refers to it in caps in the abstract and lowercase in the main text" is an observation that actually strongly supports the move and indicates a lack of awareness of how WP article title and prose writing work (it is based on mainstream usage, not "can I desperately search around for someone else doing the weird style thing I want to do and try to claim that as justification"). The fact of the matter is that specialist literature virtually always can be found that capitalizes "Special Important Stuff in Our Field" as a form of emphasis of terms of art, for speed-reading by specialists skimming the specialist materials (especially their abstracts). It's the same practice as using caps and boldfacing in field guides to reptiles or wildflowers to make entries stand out for easier visual scanning. This is not encyclopedic writing, and the first rule of MOS:CAPS is do not capitalize for emphasis. See also WP:SSF for more detailed rationales against this sort of "my favorite journal does it this way, so WP has to also" fallacy.  — SMcCandlish ¢ ≽ʌⱷ҅ʌ≼  04:55, 5 January 2017 (UTC)
I accept that Wikipedia needs guidelines on "house style" and they are very useful, but WP:NCCAPS and MOS:CAPS are only guidelines (best practices) not rules nor policy. Therefore, I think you are overstating their implied unbreakability when you claim "The fact that some sources capitalize it is irrelevant; unless virtually all of them do so consistently, WP uses lower case. There's nothing magically special about this topic that makes it an exception to the "when in doubt, do not capitalize" rule." GeoWriter (talk) 15:26, 5 January 2017 (UTC)
An appeal to violating guidelines, as you and B2C are doing, is a pretty weak argument. There is no good reason to violate the guidelines here, especially considering the prevalence of lowercase usage in sources for this term. Dicklyon (talk) 16:11, 5 January 2017 (UTC)
I'm not appealing to violating guidelines, I am only pointing out that guidelines are not rules and not policies, but they are being used by User:SMcCandlish as if they are rules, facts and unbreakable. GeoWriter (talk) 16:34, 5 January 2017 (UTC)
Well, the fact is we have these guidelines. I don't see what in SMcCandlish's comments you are reacting to. It was you who introduced the notion of unbreakability; that's not usually a property of rules in any system I'm aware of. Rules and guidelines can be broken; but why should we? Dicklyon (talk) 17:12, 5 January 2017 (UTC)
When a rule or guideline serves no useful purpose with respect to improving WP, and especially if it worsens it, it should be ignored. This is the point of WP:IAR. We disagree on whether this proposal improves or worsens WP, but please understand that for those of who see it as regressive, ignoring any rule that supports this proposal is reasonable. --В²C 22:47, 5 January 2017 (UTC)
Yet no compelling case is presented that this is "regressive" in any way. This is a routine move, removing "Specialist Capitalization for Emphasis". We do this literally hundreds of times per year, because specialists in every field on earth (except perhaps linguistics and copyediting) have a strong desire to Impose Fancy Decorative Capitalization onto Topics They Think Are Overwhelmingly Important to Their Work, which are not actually special in any way to anyone else. If we did not do this lowercasing work, virtually everything less generic than "tree" and "puppy" would be capitalized on Wikipedia, and it would be a global laughingstock of terrible writing. The vast majority of RM cases that involve style are in fact cases of overcapitalization; they account for probably 80% of the RMs I comment at. It is a constant maintenance matter, in almost every case of which someone feels Their Special Needs are not being met, but which everyone else can see is routine cleanup.

IAR never applies to WP:ILIKEIT rationales. For a rule to be ignored (and yes, guidelines are rule, just less rigid ones that policies; see WP:POLICY), the ignoring of it must result in an objective improvement to the encyclopedia, not just make some editor happy about some obscure typographic peccadillo they are trying to force on Wikipedia and encyclopedic writing from some off-WP, rarified, narrow-audience context. People keep venting about how much editorial productivity is wasted on style-related feuding. Simple solution: Stop feuding about style and just following the guidelines. We have them for a reason. There are zero guideline line items (in any of our guidelines on anything) that 100% of editors agree with, and no editor agrees with 100% of our guideline line items. We all agree to abide by WP guidelines and policies, as a group, despite them not being 100% perfect for each of our idealized reality tunnels. We do this so we have a system in which we can work instead of being in constant conflict that gets in the way of productive editing.  — SMcCandlish ¢ ≽ʌⱷ҅ʌ≼  06:22, 6 January 2017 (UTC)

  • Decapitalise. There is a common style of capitalisation of letters used to form the capitalised acronym, for simple clarity. This is not enough to make a proper name. The index is not a thing with character. VEI is not a proper name. --SmokeyJoe (talk) 23:55, 5 January 2017 (UTC)
    • Thanks for the link to Proper name. It says: "A proper noun is a noun that in its primary application refers to a unique entity, ...". Isn't Volcanic Explosivity Index exactly that? There is only one such index, as far as I know, right? --В²C 00:07, 6 January 2017 (UTC)
      • My pleasure. I do think that backroom discussions should be informed by article content, where editors can correct the facts based on reliable sources. I notice again, As you can read in the article, English is not known for hard and fast rules.
        That condition is necessary but not sufficient. Not every description of a unique entity makes for a proposer noun, in English, unlike German.
        VEI refers to a unique concept, but not a unique entity. Every volcano has, or can have assigned, its own VEI. It is a characteristic. Concepts rarely get proper names, unlike entities. --SmokeyJoe (talk) 00:48, 6 January 2017 (UTC)
        • What about Big Bang? Dow Jones Industrial Average? Philadelphia Gold and Silver Index? Value Line Composite Index? Geographical Disease Risk Index? Are these entities or characteristics? --В²C 02:48, 6 January 2017 (UTC)
            • Entities or concepts, was my distinction (not "characteristic"). A concept can be used a characteristic, the concept of VEI can be used to characterise different volcanoes. Big Bang is an extraordinary concept, a theory, given a catchy title and referred to as such. The others are definitions, involving statistics, and are simple concepts. None of these are entities. --SmokeyJoe (talk) 03:08, 6 January 2017 (UTC)
          • Big Bang is a composition title and stays capitalised as such.
            The others I would support decapitalising. They are descriptive titles. They are capitilised frequently due to more common titlecase used elsewhere, but are not capitised according to Wikipedia's chosen sentence case - leaning titlecase style. In many productions, there is a style of reproducing the title case for repetition of the title phrases in the body, minimised only in accordinace with minimising any form of repetition. It is just a matter of style, and I am happy to be persuaded otherwise if there is meaning beyond style. I am not sure of the history of Wikipedia's choice in this style, but it is very deeply entrenched, and not disagreeable in any way I have discovered. On title capitalisation, although Dicklyon tends overly strident, I find he usually makes sense and I am happy to follow his lead. I won't be nominating them myself. Noting WP:TITLECHANGES, I personally don't thing these are worth the bother changing, but if the discussion is already happening I am happy to !vote. --SmokeyJoe (talk) 03:02, 6 January 2017 (UTC)
          • I would support capitalising General Relativity before volcanic explosivity index, the first can pass as a composition title and is poorly read as descriptive, the second is clearly and accurately descriptive. Neither are proper nouns, let alone proper names. --SmokeyJoe (talk) 03:19, 6 January 2017 (UTC)
            Yep. If we're not even treating natural laws and major theories with caps, then stuff like this (and comparable things - methodologies, indices, scales, processes, procedures, schools of thought, best practices, etc., etc.) do not qualify, except of course where they are work titles, or have an embedded proper name, e.g. "the Johnson system". Even the work-title exception doesn't apply when the term is genericized beyond the context of the original publication, e.g. the overall concept of future shock versus the original book by Toffler.  — SMcCandlish ¢ ≽ʌⱷ҅ʌ≼  06:27, 6 January 2017 (UTC)
            • Most if not every supporter of decapitalizing this article's title does not even participate in geology so how would they know decapitalizing Volcanic Explosivity Index is the correct format? This is at least one of the reasons why WP articles get messed up. Those who edit outside their knowledgeable fields normally don't know what they're doing/saying, especially when they're challenging specialists in that particular field! Volcanoguy 16:59, 6 January 2017 (UTC)
              • WP:SSF is called "fallacy" for a reason; and that's it. Dicklyon (talk) 23:41, 6 January 2017 (UTC)
            • What's the rationale for preferring sentence case over title case in (ahem) titles anyway? I get it for descriptive titles that we make up, but when the title reflects the well, proper name of the article topic, why not use title case? --В²C 21:22, 6 January 2017 (UTC)
              • There's no need to invoke title case, since proper names will be capitalized in either case. I think the rationale for WP article titles being in sentence case is so that you don't need to make downcased redirects to link them when they're used in sentences. Whether you think that's a great rationale or not, you're about 15 years too late to influence that decision. Dicklyon (talk) 23:41, 6 January 2017 (UTC)
  • Oppose - I searched using Google Books Ngrams (which is case sensitive) on "Volcanic Explosivity Index", "volcanic explosivity index" and "Volcanic explosivity index". The results [13] strongly suggest that the capitalisation is the preferred option in current usage. Mikenorton (talk) 11:16, 7 January 2017 (UTC)
That level of evidence is only a very weak suggestion, since it doesn't attempt to compensate for uses that are capitalized for other reasons than treating it as a proper name in a sentence. Many (most?) of them are capitalized as "Volcanic Explosivity Index (VEI)" or "VEI, Volcanic Explosivity Index" in defining the acronym; and many are for titles and headings. Click through to the book search and you'll see that is it not close to "consistently capitalized in sources" as MOS:CAPS calls for. Where wikipedia clones and the acronym are not in play, it's overwhelmingly lowercase in books. Dicklyon (talk) 21:34, 7 January 2017 (UTC)
I checked out all the results from that search that I was able to see and found that the capped and non-capped version were about even, no prepoderance either way. I then looked at Google Scholar results for papers dating from 2010 to the present [14] and found that twice as many papers had it capped than non-capped (I just looked at the first 50) but that the commonest of all was "Volcanic Explosivity Index (VEI)", with VEI used throughout the rest of the text, exactly as we have it in our article. I see no reason why we should change what we have here. Mikenorton (talk) 16:08, 8 January 2017 (UTC)
But that is exactly the reason; your search supports my observation that the caps in sources are most often for defining the acronym; that's a style that many sources use, but one that wikipedia specifically does NOT use, per Wikipedia:Manual of Style/Capital letters#Expanded forms of abbreviations. Dicklyon (talk) 16:26, 8 January 2017 (UTC)
  • Oppose - "Volcanic Explosivity Index" is a proper name, it's the unique name of a single system of classification, so it can't be compared with "diversity index", or "consumer price index", of which there are many. @SmokeyJoe, assigning VEI values to a single eruption, or even to classify a series of events in a volcano's eruptive history, doesn't constitute creating a separate VEI. @Dicklyon, the link you provide to the Google search, the results do not show "volcanic explosivity index" to be "overwhelmingly lowercase in books" - if you go past the first page of the search results (i.e. to the first three pages of results, which is still a small sample) then "Volcanic Explosivity Index" is still ahead by a wide margin. Cheers, Bahudhara (talk) 01:58, 8 January 2017 (UTC)
  • Oppose. It's a proper noun because it is commonly capitalized. Calidum 21:06, 9 January 2017 (UTC)
The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Age of Holocene[edit]

Why is the age of the Holocene variously described as 10,000 and 11,700 years?Royalcourtier (talk) 01:37, 27 March 2017 (UTC)

possible VEI 9[edit]

a supervolcano said to be one of of the largest eruption on the planet , in eastern canada this might be one to add for a VEI9? — Preceding unsigned comment added by Joshoctober16 (talkcontribs) 05:18, 15 December 2017 (UTC)

The page doesn't say all 12000 km3 of it occurred in one eruption. At least 10000 km3 has to have come from a single explosive eruption in order to qualify for VEI 9. Given that this appears to be a nonexplosive flow complex, it doesn't count.--Jasper Deng (talk) 06:11, 15 December 2017 (UTC)

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