Yellowstone caldera in Wyoming. Whether we like it or not, it is now permanently associated with the term "supervolcano." Image: Pascal / Flickr. As many of my regular readers know, I don't particularly care for the term "supervolcano." In my mind, it is the epitome of a sensationalist media buzzword that really lacks any scientific background in its meaning -- it has always been said that the 2005 BBC/Discovery Channel docudrama Supervolcano put the world into common parlance, and it seems to have stuck. But after a recent Twitter discussion about the word and its overuse in science media, I decided I wanted to get to the bottom of the "supervolcano" and figure out just when did it arrive on our linguistic shores and who we can blame (or credit, I suppose) for the term. What I found out was more than surprising to me, with documents almost a century old, sordid characters and a lot of tail wagging the dog when it comes to the rise of "supervolcano" in media use and especially scientific literature. It all starts back in 1925. The Oxford English Dictionary seems like a good place to start. Yes, the word does appear in the lexicon of the English language. They define it as "an usually large volcano capable of producing a massive eruption" (we'll get back to this definition later on). The first attribution of the word does go all the way back to 1925, in a book called Conquering the World by Helen Bridgeman. The book is a travelogue and captures scenes from around the world during the early part of the twentieth century. In there, we find "supervolcano" for the first time, but it has nothing to do with volcanoes. Instead, Bridgeman is describing a sunset in Indonesia (fitting, isn't it?), where she says "There are no such sunsets anywhere as those of the Indian Ocean, when the light cirrus clouds..become one mass of molten fire—a super-volcano, as it were, upside down." There you have it, patient zero for "supervolcano" in the English language ... however, it just doesn't seem fitting to have this word come from the description of a sunset rather than from something geologic. To get there, we have to jump to 1949. From what I can find and what the OED lists, supervolcano didn't show up again until the late 1940s. However, the reason the word was used in 1949 has everything to do with 1925 ... just not Mrs. Bridgeman. In the same year as Conquering the World, E.T. Hodge (Professor of Economic Geology at University of Oregon ... but we can forgive him) wrote a book called
Mount Multnomah, Ancient Ancestor of the Three Sisters.
In it, he describes his theory that the Three Sisters in Oregon (South, Middle and North) were actually remnants of a much larger volcano, his Mount Multnomah. He never actually uses the word "supervolcano" in the book, so why are we talking about Hodge's book? Well, in 1949, Howel Williams published the classic work The Ancient Volcanoes of Oregon, where he tackles the origins of such volcanic areas as Three Sisters. Now, Williams doesn't use the term "supervolcano" either, but in a review of his book by F.M. Byers in the Journal of Geology, Byers mentions that Williams never even mentioned Hodge's supposed Mount Multnomah, saying "
In the discussion of The Three Sisters' region no mention is made of E. T. Hodges' ancient supervolcano, Mount Multnomah."
So, we've tracked down what I think is the first geologic use of the term. Now, if we're looking at the context of the usage, it is very different than today's "giant eruption" connotation. Instead, Byers is likely using it to mean the amalgamation of three already large volcanoes in Oregon, the Three Sisters (see below), thus making it a "supervolcano." Same word, but what I think is a different sense, instead referring to combining multiple volcanoes into a larger volcano rather than a volcano that could produce a massive eruption.
Three Sisters in Oregon, not the home of a "supervolcano" called Mount Multonomah. Image: US Geological Survey. After Byers, it took us another 50 years before "supervolcano" showed up again. Well, once, in 1977, it appeared in a Science News article about massive volcanoes in the solar system, but that seemed to be a one-off usage by a prescient journalist. It wasn't until 2000 that "supervolcano" reappeared in the scientific literature -- oddly enough in two different articles in different disciplines that both came out in September of that year. The first is by Henry Harpending and Alan Rogers in the Annual Review of Genomic and Human Genetics, where they mention that "
an environmental catastrophe such as an ice age or the Toba supervolcano could have reduced the population of each species"
(referring to early humans and primates).This statement links back to the 1992 Nature article by Michael Rampino concerning the supposed genetic bottleneck caused by the eruption of Toba 74,000 years ago. Rampino never said "supervolcano" in that paper, but did refer to it as a "super-eruption," so it was Harpending and Rogers that modified the term to supervolcano in their usage. So, the first use of supervolcano in scientific literature in 50 years came out of an anthropologic discussion. (Harpending, by the way, has somewhat of a sordid history, being a proponent of the idea that European genetic superiority allowed them to conquer the world.) Also in 2000, D.K. Chester and others also used the term "supervolcano" in a paper called "The increasing exposure of cities to the effects of volcanic eruptions: a global survey" in Environmental Hazards. However, it isn't in the text but rather a reference to an article in the Independent in 2000 about scientists testifying before Parliament about the threat of a "
supervolcano that could blot out the sun and bring a global winter.
" So, not directly used, but it does appear that the term was picking up usage. Now, why is that? I suspect it is because of a book by David Keys in 1999 called Catastrophe: an investigation into the origins of the modern world, where he suggests implicates a massive eruption that spurred global cooling in 535 A.D. OK, so where did he get his idea? Apparently from scientist (Ken Wohletz) at Los Alamos National Laboratory who supported a theory (that no evidence has been found) of a massive volcano between Sumatra and Java (where modern day Anak Krakatau is). So, again, an amalgamation of volcanoes but this time, it does also include a very large eruption. (Note: Jacob Lowenstern, head of Yellowstone Volcano Observatory, noted in a comment below that another source for the spike of "supervolcano" around 2000 was the BBC/Horizon documentary "Supervolcanoes". The program definitely seems inspired by Keys as well). We can't blame Keys and Wohletz directly as they never themselves use the term "supervolcano." Instead, this whole discussion comes from CCNET, which is more concerned about near-Earth objects (asteroids and comets) than volcanoes, but they titled they article on Wohletz's theory "
Super-volcano may have triggered global cooling in 536 A.D.
" (Interesting note: another volcano has now been fingered for the 535-536 A.D. global cooling) So, where are we? Keys brings back the idea of massive eruptions that can impact global climate, with inspiration (likely) from Rampino's work at Toba. Anthropologists start using the term "supervolcano," likely to make it seem even flashier than just "volcano" in a paper about genetic diversity during early human evolution. Chester then refers to a news article that uses the word in the title. But when does it get into the geologic literature? It takes a while although it gets used in other disciplines. In 2001, the word shows up in journal articles from Near East Archeology (referring to Toba) and
Journal of Radioanalytical and Nuclear Chemistry
(referring to Yellowstone, for what might be the first time). Also, the popular press book Volcanoes by Peter Clarkson uses it to talk about massive eruptions in Idaho. However, it isn't until 2002 that it shows up in geologic literature, again, starting with asteroid impact theory (namely, alternatives). C.R. Chapman uses the term in a Geological Society of America publication called "Impact lethality and risks in today's world: Lessons for interpreting Earth history" and a paper in The Holocene refers to a supervolcano when discussing European bog oaks of all things, but does so to refer back to Keys' ideas of a volcanic eruption in 535 A.D. Neither of these actually define a "supervolcano," but rather just mention them offhandedly. In fact, the first truly geologic publication focused on a "supervolcano" that can be found in Google Scholar is from 2002 by the infamous R.B. Trombley discussing prediction of eruptions at Yellowstone. Trombley was an amateur geologist who made his "Southwest Volcano Research Centre" seem like a major research center when it was really his trailer. He duped people into buying his false "eruption prediction" software and was interviewed during the eruption of Eyjafjallajökull. It was then when it was found out that he was a fraud. That being said, he attributes "supervolcano" to a BBC documentary in 2000, likely based on Keys' Catastrophe book. So, the use of "supervolcano" in geology was launched, in a sense, by one of its greatest frauds. After 2002, the term seems to live in popular press sources (like right here at Wired) until 2004, when supervolcano gets its first real volcanologist use (well, after Trombley). In a paper from Bulletin of Volcanology by Ben Mason in 2004 (co-authored by David Pyle and Clive Oppenheimer) titled "The size and frequency of the largest explosive eruptions on Earth," the term "supervolcano" shows up as a keyword for the article. In it, Mason lays out the evolution of terminology for giant eruptions:
Qualitative terms suggesting the ‘enormity’ of particular events abound in the literature, but are only rarely defined in terms of a quantitative measure of size. For example, Simkin and Siebert (1994) list the terms ‘cataclysmic, paroxysmal or colossal’ to describe events larger than about 0.1 km^3 of tephra. On a larger scale, events ejecting ~300 km^3 of magma have been termed ‘mega eruptions’ (Zielinski et al. 1996), ‘gigantic eruptions’ (Huff et al. 1992) and ‘great eruptions’ (Rose and Chesner 1987). In recent years, the additional qualitative, but highly evocative, terms ‘supereruption’ and ‘supervolcano’ have caught the popular imagination; and these terms are now beginning to creep into the published literature (Rampino and Self 1992; Rampino 2002). This study concentrates on defining the scale of the very largest eruptions using established quantitative concepts of ‘size’ from the literature. (my emphasis)
Those references by Rampino actually only use "super-eruption," but the point is the same: The term is really just one that is used for sensationalism (Ben, Clive and David are off the hook). Other papers used the term in the continued discussion of the global cooling of 535 A.D., but it wasn't until 2005, when the BBC/Discovery docudrama called Supervolcano came out that the term really caught hold -- but they weren't alone. Supporting literature for the movie by Jacob Lowenstern and Bill McGuire have the term in their titles (by no fault of their own, I would guess). It also seems to be the point where Yellowstone and "supervolcano" were permanently wed. It even seems that the BBC documentary prompted the U.S. Geological Survey to create a rough idea of what "supervolcano" means to tackle the deluge of questions:
The term "supervolcano" implies a volcanic center that has had an eruption of magnitude 8 on the Volcano Explosivity Index (VEI), meaning the measured deposits for that eruption is greater than 1,000 cubic kilometers (240 cubic miles). (my emphasis)
. Note that it isn't truly a definition but rather a sense of the meaning (by use of "implies") and isn't close to the volumes mentioned in Mason and others (2004). After this, it was all down the slippery slope.
Google Ngram search of books for the use of "supervolcano" from 1970-2008, showing the sharp increase by 2005 onward. Image: Erik Klemetti / Google Ngram. Doing a quick survey using Google Scholar, I found that in 2004, "supervolcano" was used 20 times while in 2005, it was used 35 times. Not all of this is peer-reviewed scientific literature, but after the BBC movie, "supervolcano" jumped to 66 occurrences in 2006 and almost 150 by 2010. (Note: Again, from Dr. Lowenstern's comment below, he mentions the 2005 Geological Society of London working group titled "Super-eruptions." The report from the working group mentions "supervolcano" once, but definitely goes all in with "super-eruption".) Probably the biggest event that allowed "supervolcano" to become a (nearly) accepted term in the geologic literature was a special issue in 2008 of the magazine Elements, put out by the Geochemical Society, that was dedicated to (and called) "Supervolcanoes." This issue was full of a who's-who in volcanology and petrology, so if the term needed any professional backing to be accepted, it sure got it. Even across the internet and books, the use of "supervolcano" as a word has taken off since the BBC movie and the issue of Elements. Just this year alone, the word has appeared in 122 citations in Google Scholar, putting this year on pace to be the most supervolcanic year yet. In terms of web searches, the big peak was right around the release of Supervolcano, but Google Trends clearly shows that it bumps back up every time a news sources throws the term around to spread of sensationalist news about some large volcanic event.
Google Trends graph for use of the keyword "supervolcano" from 2004-2013. Peaked in 2005 around the release of the movie, but doesn't ever go away. Image: Erik Klemetti / Google Trends So, where does that leave us? For one, we might be stuck with "supervolcano" ... and I think I might be OK with that, but with a caveat. At this point, the term "supervolcano" is so vaguely defined that almost any large volcanic event gets called this. However, these events, by the loose USGS definition, are exceedingly rare. All the talk of supervolcanoes, and there have been exactly zero in the the Holocene (last 10,000 years). By the USGS use, Toba is the most recent at ~74,000 years ago. And 1000 km^3 is a lot material to erupt -- that is 40 times Pinatubo's 1991 eruption, 6.25 times Tambora. What the term does imply across much of its uses is a massive explosive eruption, not effusive lava flows. Something like the supposed giant Tamu Massif volcano wouldn't be a "supervolcano" as such. In fact, without tight age constraints to show that a single eruption produced over 1000 km^3, the term shouldn't even be used. Now, if I had my druthers, I would say a better term would be a "supereruption" from a volcano, as for all of the implicated systems like Yellowstone and Toba, much of their history is dominated by eruptions that were clearly not "super." However, they have produced massive eruptions, which, as a class, could be consider "super" as they are so much bigger than any other explosive eruptions and are so much rarer than other eruptions that they deserve their own designation. That being said, if you want to designate those volcanoes that have produced such an eruption in the past as such, I can think of worse things than "supervolcano." There you have it. This is how a term that started as a nice way to describe a sunset, was then used to derisively refer to a failed theory and then popped back up after half a century thanks to a popular press book became a piece of our geologic lexicon. It has been used often but poorly defined, but its permeation into the scientific literature means we can't really just say it is a media buzzword. Sure, its use might raise the profile of the paper, but so does T. Rex and should we stop using that term? As long as we can use the term appropriately -- namely, for massive explosive eruptions over 1000 km^3 (for super-eruptions) and the volcanoes from which they are derived (for supervolcanoes), at least we're taking the first steps in wrangling this term that raises so many hackles.
{Special thanks to all who participated in the Twitter discussion yesterday and especially Dave McGarvie for help with the word origin}
