Shanaka de Silva
Stephen Self- 1College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States
- 2Earth and Planetary Science Department, University of California, Berkeley, Berkeley, CA, United States
Although evocative, the term supervolcano has a checkered history of hyperbole and misuse to the point that it seems unprofessional. However, “supervolcano” is firmly embedded in volcanological discourse and we make the case that it is useful if defined and used correctly. To this end we examine the etymology of supervolcano and demonstrate its’ dependence on the term supereruption. We build on the work of colleagues to propose that supervolcano be restricted to a volcano that has been the site of at least one silicic explosive eruption of Magnitude of 8 (M 8) or greater. Based on this, nine active supervolcanoes are found on the Earth today and although all are calderas, we contend that referring to them simply as large calderas or caldera complexes obviates clear magmatic, volcanological, and structural extremes that distinguish supervolcanoes from other caldera complexes. Such supervolcanoes may produce eruptions that exceed M 9 but we stress that most eruptions from supervolcanoes are actually small effusive eruptions. Basaltic explosive supereruptions remain enigmatic on Earth and therefore we advise against the use of supervolcano for any basaltic volcano or province on Earth.
Introduction
Natural hazards cover a range of scales, and it is common practice in the Earth sciences to differentiate the extremes through the use of superlatives (superstorms, supercells, superfaults, megafloods, megaquakes, megatsunami, super-greenhouse, and super-mountains among others). This is a double-edged sword. On the one hand superlatives feed into hyperbole and can be open to misuse, most obviously as click-bait headlines or quotes. As aptly put by Janine Krippner of the Global Volcanism Program referring to mega-tsunamis “Headlines take the smallest hint of truth and turn it into an irresistible bogeyman, causing real stress and harm around the world”. On the other hand, superlatives have their value. Scientifically their use recognizes the extremes of natural phenomena and conveys the rarity beyond historical experience, but perhaps as important, superlatives ignite public attention and are often the pathway to greater awareness of hazards and the threats they present to society—and of the excitement and importance of Earth Science. Here we look at superlatives in volcanology, in particular the use and abuse of the term supervolcano. Like it or not, we find it is here to stay, we accept this, and provide this commentary for its correct use.
The Origins of “Supervolcano”
Volcanologists have tended to shy away from superlatives with the exception perhaps of George Walker’s “ultraplinian” eruption (Walker, 1980), which has recently been shown by Houghton et al. (2014) to be based on an incomplete characterization of a complex deposit emplaced into shifting wind conditions and thus the type no longer exists. The term supervolcano, which often raises eyebrows and elicits sighs of disapproval as being corny, clichéd, and unscientific, has a checkered history of misuse. This is primarily in the general media, but includes geologic peer-reviewed journal publications, and has prompted us to write this piece. We note that there are efforts in the blogosphere that attempt to redress the balance and provide some rigour (Andrews, 2018), but these, by their nature, do not provide a scholarly assessment.
The term supervolcano goes back quite a long way. Apparently, USGS geologist Frank M. Byers Jr. used the term in a review of a book in 1949, referring to a proposed set of distributed volcanoes around the Three Sisters in Oregon, that turned out to be specious (Wikipedia, 2021). About 2003 the term supervolcano was introduced in the eponymous movie being developed by Discovery Channel/BBC TV but with unfortunate hyperbole—Is Yellowstone overdue? was the titillating by-line for the movie - and there was no formal definition (Discovery Channel, 2005). Lowenstern (2005) and Lowenstern et al. (2006) appear to have the first formal use and definition of the term which was subsequently modified to the currently accepted formal definition of “supervolcano” in Miller and Wark (2008)—in their introduction to the journal Elements Supervolcanoes issue What makes a volcano super? There a supervolcano refers to “a volcano that was the source of at least one supereruption”. The United States Geological Survey has the following formal definition on their website “The term “supervolcano” implies a volcanic center that has had an eruption of magnitude eight on the Volcano Explosivity Index (VEI), meaning the measured deposits for that eruption is greater than 1,000 cubic kilometers (240 cubic miles)” (USGS website accessed 5 January 2022). As we will see below, even this definition from a trusted source is problematic.
The concept of super-eruptions has been in volcanological discourse since at least 1984 when Bob Christiansen of the USGS (with reference to Yellowstone volcano) wrote “superexplosive eruptions of magnitudes that have seldom, if ever, been recorded in human history….” (Christiansen, 1984). In 1992, Rampino and Self coined the term supereruption in a paper on the Youngest Toba Tuff (YTT), the most recent caldera-forming eruption from Toba caldera, Sumatra, but did not define the term. We note that some works refer to the YTT eruption as a mega-eruption (Zielinski et al., 1996) again without any formal definition. It was in a 2005–2006 report and paper (Sparks et al., 2005; Self, 2006) that supereruption was defined as one that erupted a minimum 1,000 km3 of rhyolitic tephra or pyroclastic deposits, which is ∼450 km3 of magma or dense rock equivalent (DRE) or >1 × 1015 kg of felsic/rhyolitic magma.
Two popular classification schemes for volcanic eruptions are 1) the Volcanic Explosivity Index (VEI) of Newhall and Self, (1982), a semi-quantitative logarithmic scale that classifies explosive volcanic eruptions based on erupted volume, eruption column height, and intensity, and 2) the Magnitude scale developed by Pyle (1995, 2000), which is based on the mass of magma erupted. Confusion arises because the term magnitude is variously used to imply scale, intensity, volume of magma or deposits, as well as mass of magma in volcanology. It was originally used in the VEI scale as a measure of volume and intensity, hence the above USGS reference to a VEI of magnitude 8. This has unfortunately led to conflation of volume and mass, deposits and magma, in particular. We choose not to enumerate the many instances that we have found, even in peer-reviewed literature, but suggest that, going forward to avoid this, Pyle’s measure Magnitude M, be the primary measure of magnitude (as a capitalized and italicized M). If the term “magnitude” is used in any other way the context should be clearly specified. Thus, in these classification schemes a supereruption has a Magnitude of 8 (M 8) or greater and a VEI of eight or greater–we would recommend not using “magnitude” with VEI to avoid confusion.
Problems, Pitfalls and Inconsistencies
The definitions above rely on measures (volume, intensity, eruption column height, DRE, M) that are unfortunately inconsistent. It is telling that in our best available databases such as LaMEVE (Crossweller et al., 2012) and Mason et al. (2012) more than 50% of the eruptions classifed as ≥ M8 are either missing critical measures or provide inconsistent classification criteria. Most of this is due to the inherent imperfection of the geological record in terms of preservation but there are also methodological inconsistencies.
Volume estimates of pyroclastic deposits are notoriously difficult even in the youngest eruptions due to exposure and preservation and this is compounded with age and environment. Supereruptions, most of which are geologically old (pre-Holocene), and with products that may extend 1,000s of kilometers from source, are even more challenging to measure. Although a few attempts have been made to provide rigorous volume estimates (e.g. Folkes, et al., 2011; Cook et al., 2016), even these require inferences and model-based extrapolations to make these half-an-order-of-magnitude estimates at best. A case in point is for the famous Youngest Toba Tuff eruption which is one of the most infamous supereruptions and the volume estimations are the among the most rigorous that are available. Here the original dense rock equivalent (DRE) magma volume estimate of 2,800 km3 (Rose and Chesner, 1987) has been reconstructed to 5,300 km3 DRE by Costa et al. (2014). Both these estimates require assumptions and model-based corrections and rules of thumb that are now common practice and demonstrate that volume estimates of large explosive eruptions are largely reconstructed, with only rare attempts to document uncertainties. The problems are compounded by assumptions made in converting tephra volumes to DRE and those in turn to masses of magma based on densities that are at best averages that attempt to normalize variable tephra densities. Given these issues the community accepts that volume and mass estimates of supereruptions (and all but the smallest explosive eruptions) are at best hemi-order of magnitude estimates.
It should be clear then that the definitions of supervolcano (and supereruption) that specify measured volumes, and include both VEI and Magnitude (M), are at best hemi-order of magnitude distinctions that can easily lead to inconsistencies, as cases emerge of eruptions that may have volume estimates that do not classify as VEI 8, whereas M, the mass estimate, may.
Large Basaltic Eruptions are not Supereruptions and Therefore There are no Basaltic Supervolcanoes
Another issue in defining supervolcano, is that massive eruptions of flood-basalts have been referred to as supereruptions (Self et al., 2014) because they fit the mass criterion (M 8). Work on continental flood basalt provinces (CFBPs) or large igneous provinces (LIPS), such as the Columbia River Basalts (Tolan et al., 1989; Reidel et al., 2013) and other provinces (Self et al., 1998; Self et al., 2008; Bryan et al., 2010) has shown that most eruptions during LIP formation do have dense-rock volumes comparable to those needed for VEI 8 or masses needed for an M 8 - due to the density difference between basalt and rhyolite a flood basalt eruption only needs to be >360 km3 to have a mass of 1 × 1015 kg. In this context, CFBPs and LIPs, could be considered to be supervolcanoes and often are, particularly in the press (e.g., Geolsoc.org, 2013; Forbes.com 2021). However, we propose that this is misleading. The term supereruption is synonymous with explosive silicic (sensu latu including intermediate compositions like silicic andesite and dacite) volcanism. As such, beyond magnitude, intensity, as a proxy for explosivity, is also a defining criterion. By association, supervolcano should also be restricted to volcanoes that produce explosive supereruptions. Under this definition it should be clear that the world’s largest volcanoes (e.g., Pūhāhonu (Garcia et al., 2020); Mt. Tamu, Shatksy Rise, (Sager et al., 2013), and the above referred-to Kerguelen Plateau) are not known to have produced a supereruption, and thus should not be referred to as supervolcanoes. Explosive basaltic volcanism (Parfit, 2004; Houghton et al., 2014) is increasingly being recognised in the geological record. Such eruptions maybe an exception, but typically involve magma-water interaction and have not been unequivocally documented to be on the scale of supereruptions. One exception may be the Ash +19 in the North Atlantic Igneous Province (Stokke et al., 2020), but whether this is the product of a single caldera-forming eruption is unclear. Thus, although some flood basalt provinces and LIPS are claimed to have produced basaltic and silicic volcanic volumes that are the products of supereruptions (Bryan et al., 2010) the discrete sites of eruption for these which could be termed supervolcanoes are unknown.
What is a Supervolcano?
Based on the foregoing, we propose that a supervolcano is a volcano that has been the site of at least one silicic explosive eruption of Magnitude 8 (M 8) or greater. As such the term supervolcano is inexorably linked to the term supereruption and this in turn is at present restricted to silicic explosive eruptions of >M 8. Physically, supervolcanoes differ from other volcanoes not only in that the biggest eruptions are outsized and their impact is potentially far greater than normal eruptions, but the appearance of the volcano itself after eruption is also distinctive: it does not conform to the common image of a volcano. All the volcanoes that fall into this definition are large calderas, often resurgent, and are extensive depressions (100s to 1,000s of km2 in area). Such supervolcanoes are unknown in basaltic provinces. In Table 1 we have curated a list of the bona fide active supervolcanoes of which we are aware.
TABLE 1. Known active† supervolcanoes. †demonstrated eruptive activity <100 kyrs.
The list in Table 1 may at first appear to reflect the potential bias of privilege in the sense that most of the identified supervolcanoes are in resource and opportunity endowed regions. Thus, there might be other supervolcanoes we have not identified in resource and opportunity limited regions that have been less volcanologically explored. However, we would argue that any bias is limited, particularly for young “active” systems. First the geodynamic conditions to develop supervolcanoes are well known and in the last 100,000 years this has not changed. Second, scientific colonization and the advent of satellite monitoring has resulted in flattening of the Earth in terms of the search for interesting active geological phenomena and we would be aware of any interesting anomalies on the continents - beneath the ocean is a different issue, but supervolcanoes are less likely to develop in these settings. Supporting our position that bias is probably limited is that in the compilation of VEI 7 eruptions in Newhall et al. (2018) at least half are in resource and opportunity limited nations.
Supervolcanoes are large complex calderas, so why not simply refer to them as such?
Although they are calderas, simply calling supervolcanoes large calderas or caldera complexes (Poland, 2019; Morton, 2021) ignores some key magmatic, volcanological, and structural distinctions from the smaller Krakatau-type (10s of km2) and nested caldera complexes that form by collapse of the summits of composite volcanoes.
Calderas in general show a size to volume-erupted relationship (Smith, 1979; Spera and Crisp, 1981) indicating a first order relationship between spatial dimensions and geometry of the pre-eruptive magma reservoir and the associated stress field that controls caldera collapse (Lipman, 1997; Gudmundsson, 1998; Folch and Marti, 2004; Kennedy et al., 2004; Scandone and Acocella, 2007). The outsized dimensions of magma reservoirs that birth supereruptions are the result of high crustal magmatic fluxes and long thermal histories that pre-condition the crust to promote storage, growth, and retard eruption in contrast to smaller calderas and caldera complexes (e.g. de Silva, 2008; Karlstrom et al., 2010; Cashman and Giordano, 2014; de Silva and Gregg, 2014). The intersection of these factors is reflected in the magnitude-frequency of large eruptions, >M 7 being statistically different from those of smaller eruptions implying different mechanisms controlling these eruptions (Deligne et al.,(2010); Mason et al., 2004; Deligne et al.,(2010); Tatsumi et al., 2018). M 8+ eruptions like that of the 74,000 year old Youngest Toba Tuff from the Toba caldera, Sumatra, and the 2.1 Ma Huckleberry Ridge Tuff from the Island Park caldera, Yellowstone, United States, are further distinguished by their magnitude-frequency (Pyle, 1998). These statistical distinctions are consistent with studies that demonstrate that the physical mechanisms of eruption triggering and caldera collapse initiation from such large magma reservoirs are indeed distinct. Field studies that document the characteristics of the deposits from supereruptions and modelling efforts that consider the thermal evolution of caldera-related magmatic system have shown that there is distinction between the largest and smallest systems (Sparks et al., 1985; Gudmundsson, 1998; Christiansen, 2001; Jellinek and DePaolo, 2003; Gregg et al., 2012, 2013; Cashman and Giordano, 2014). To summarize briefly, Krakatau-type calderas are triggered by internal overpressure in magma reservoirs that leads to an initial plinian eruption that evenutally underpressures the reservoir leading to caldera collapse. The magma reservoirs associated with supervolcanoes undergo a different pressure evolution where internal overpressure rarely develops, retarding eruption and promoting growth of the magma reservoir (de Silva and Gregg, 2014). Eventually the dimensions of the magma reservoir reach a threshold where the strength of the reservoir roof is exceeded and eruption is initiated as gravitational roof foundering occurs.
For these reasons, we argue that a term that distinguishes large calderas that are the result of supereruptions is useful as it captures important volcanological distinctions. Like it or not, supervolcano has precedence and implicitly includes important volcanological and magmatic distinctions that differentiate these from other calderas and caldera complexes.
Not all eruptions from supervolcanoes are supereruptions
A common source of confusion is that supervolcanoes do not just produce supereruptions. The fact is that there are no known supervolcanoes that do not emit smaller eruptions as well and the most likely eruption in the near future from any of the restless supervolcanoes on Earth is likely to be a small eruption. This is an important point of agreement with colleagues who would reject the term supervolcano. The plain fact is that the most frequent eruptions from supervolcanoes are actually small eruptions, most commonly effusive lava eruptions. At Toba, several small effusive eruptions continued for at least 13,000 years after the 74 ka climactic Youngest Toba Tuff supereruption (Mucek et al., 2021). These are individually of the order of only 0.1–1 km3, four or five orders of magnitude smaller than the climactic eruption. At Yellowstone dozens of lava eruptions have occurred since the supereruption 631,000 years ago, and until as recently as ∼70,000 years ago with the most recent having a volume of 70 km3 (Table 1; Christiansen et al., 2007; Watts et al., 2012). The Taupo supervolcano in New Zealand has had one supereruption, the 26.5 ka Oruanui eruption (Wilson, 2001), but has had many smaller eruptions before and since including the famous Taupo Eruption ∼1800 years ago that measures approximately as an M 6.9 and VEI 5. Small effusive post-climactic eruptions as seen at Toba, are referred to as ring-fracture or post-caldera eruptions (e.g. Smith and Bailey, 1968) and represent leaks of new or remnant magma as the caldera system relaxes after the catastrophic disruption of the climactic eruption. In this sense these eruptions are akin to aftershocks after an earthquake (or megaquake in this case) in that they are the residual effects of the major event - the afterparty to the big dance.
We note that precursors to the “big one” have rarely been described because the evidence is often destroyed and consumed by the climactic eruption. One exception is in the 27 Ma La Garita caldera of the San Juan mountains of Colorado, where the VEI 6 (∼200 km3) Pagosa Peak dacite preceded the massive M 9 Fish Canyon Tuff eruption by anywhere from 15 to 78 ka (Morgan et al., 2020). The only evidence for a post-climactic eruption at La Garita is the 1 km3 Nutras Creek Dacite.
What should not be called a supervolcano?
This goes to the crux of the abuse and misuse of supervolcano due to a lack of attention or awareness of the formal definition established by Miller and Wark in 2008 and the conflation of the volume and magnitude measures. There are some caldera volcanoes that over their lifetime have exceeded 450 km3 in cumulative output of felsic magma, but have never had a supereruption, per se. These are not supervolcanoes. One of the most common misrepresentations is Campi Flegrei, the famous European or Italian “supervolcano” or “Europe’s Yellowstone” (a Google Search brings up many of such comparisons from Newsweek, National Geographic, Wired, and the BBC), which does not fit its’ proposed status. The so-called Campanian “supereruption” is currently estimated at 181–265 km3 DRE, a mass of 4.7–6.9 × 1014 kg, a magnitude (M) of 7.7–7.8 and a VEI of 7 (Silleni et al., 2020). It is possible that when more work is done, Campi Flegrei may rise to the status of a supervolcano, but at present it does not fit the bill as defined above. However, we do note that given its location, a future eruption with a magnitude comparable to the Campanian Ignimbrite would be even more catastrophic than a true supereruption in a remote region like the Altiplano/Puna of the Andes, for instance.
Other examples of potential supervolcanoes include the Ata Caldera in Kyushu, Japan, the source of the ∼110 ka Ata Ignimbrite (Aramaki and Ui, 1966; Matsumoto and Ui, 1987) and the Taal and Laguna de Bay calderas in the Philippines that appear to be associated with major eruptions before ∼130 ka ago (Torres et al., 1995); these last two are particularly interesting because they were of dominantly intermediate composition. However, these, and others such as Corbetti-Asawa in Ethiopia which apparently had a massive eruption ∼670 ka ago (Newhall et al., 2018), remain insufficiently studied to fully assess their inclusion. There are probably several others, but they are insufficiently documented for us to include them here.
Concluding Summary
The Earth Sciences uses superlatives to emphasize extreme events and phenomena. The subdiscipline of volcanology should not be any different. Although subject to misuse and hyperbole, superlatives bring attention to the real science and can add value. Supervolcano is such a term. Rather than throw our hands up in frustration and ignore it, we should recognize that the term is here to stay and work to ensure its correct usage. We believe it is useful and should be retained. The term supervolcano is intimately linked to the term supereruption defined as an explosive silicic eruption of Magnitude 8 (M 8) or greater. We clarify the definition of supervolcano as a volcano that has been the site of at least one explosive silicic eruption of Magnitude of 8 (M 8) or greater. The sites of eruption are typically large calderas, but referring to supervolcanoes as simply calderas or caldera complexes (e.g., Poland, 2019) obviates the clear magmatic, volcanological, and structural extremes that distinguish supervolcanoes from other caldera complexes. It is important to understand that whereas the largest supervolcanoes may produce eruptions as large as M 9 (1016 kg of magma), most eruptions from supervolcanoes are actually small effusive eruptions. Basaltic explosive supereruptions remain enigmatic on Earth and their association with catastrophic caldera-formation is unknown; therefore, we advise against the use of the term supervolcano for any basaltic volcano or province on Earth.
Data Availability Statement
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.
Author Contributions
SdeS and SS jointly concieved the paper, compiled data, and wrote paper.
Conflict of Interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Publisher’s Note
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.
Acknowledgments
We appreciate an informal review of an early version of this work by Jake Lowenstern that helped us clarify this contribution. We are very appreciative of journal reviewers PP and JC who provided valuable perspectives that challenged us to be more rigorous about our intent and message. Editor Valerio Acocella is thanked for his editorial handling and support. Publication was made possible in part by support from the Berkeley Research Impact Initiative (BRII) sponsored by the UC Berkeley Library.
References
Andrews, R. (2018). Here is What a Supervolcano Actually is and What it is Definitely Not. Available at: https://www.forbes.com/sites/robinandrews/2018/07/23/here-is-what-a-supervolcano-actually-is-and-what-its-definitely-not/?sh=7ce50cc94fee.
Aramaki, S., and Ui, T. (1966). Ata Pyroclastic Flows and the Ata Caldera in Southern Kyushu, Japan. J. Geol. Soc. Jpn. 72, 337–349. doi:10.5575/geosoc.72.337
Bryan, S. E., Peate, I. U., Peate, D. W., Self, S., Jerram, D. A., Mawby, M. R., et al. (2010). The Largest Volcanic Eruptions on Earth. Earth Sci. Rev. 102, 207–229. doi:10.1016/j.earscirev.2010.07.001
Cashman, K. V., and Giordano, G. (2014). Calderas and Magma Reservoirs. J. Volcanol. Geotherm. Res. 288, 28–45. doi:10.1016/j.jvolgeores.2014.09.007
Chesner, C. A. (2012). The Toba Caldera Complex. Quat. Int. 258, 5–18. doi:10.1016/j.quaint.2011.09.025
Christiansen, R. L., Lowenstern, J. B., Smith, R. B., Heasler, H., Morgan, L. A., Nathenson, M., et al. (2007). Preliminary Assessment of Volcanic and Hydrothermal Hazards in Yellowstone National Park and Vicinity. U.S. Geological Survey Open-File Report 2007-1071, 94 pp. Reston, VA.
Christiansen, R. L. (2001). The Quaternary and Pliocene Yellowstone Plateau Volcanic Field of Wyoming, Idaho, and Montana. United States Geological Survey Professional Paper 729-G, 145pp. Reston, VA.
Christiansen, R. L. (1984). “Yellowstone Magmatic Evolution: Its Bearing on Understanding Large Volume Explosive Volcanism,” in Explosive Volcanism: Inception, Evolution, and Hazards (Washington, D.C.: National Academy Press), 8484–9595.
Cisneros de León, A., Schindlbeck‐Belo, J. C., Kutterolf, S., Danišík, M., Schmitt, A. K., Freundt, A., et al. (2021). A History of Violence: Magma Incubation, Timing and Tephra Distribution of the Los Chocoyos Supereruption (Atitlán Caldera, Guatemala). J. Quat. Sci. 36 (2), 169–179.
Cook, G. W., Wolff, J. A., and Self, S. (2016). Estimating the Eruptive Volume of a Large Pyroclastic Body: The Otowi Member of the Bandelier Tuff, Valles Caldera, New Mexico. Bull. Volcanol. 78, 10pp. doi:10.1007/s00445-016-1000-0
Costa, A., Folch, A., Macedonio, G., Giaccio, B., Isaia, R., and Smith, V. C. (2012). Quantifying Volcanic Ash Dispersal and Impact of the Campanian Ignimbrite Super‐Eruption. Geophys. Res. Lett. 39, L10310. doi:10.1029/2012gl051605
Costa, A., Smith, V. C., Macedonio, G., and Matthews, N. E. (2014). The Magnitude and Impact of the Youngest Toba Tuff Super-Eruption. Front. Earth Sci. 2, 16. doi:10.3389/feart.2014.00016
Crosweller, H. S., Arora, B., Brown, S. K., Cottrell, E., Deligne, N. I., Guerrero, N. O., et al. (2012). Global Database on Large Magnitude Explosive Volcanic Eruptions (LaMEVE). J. Appl. Volcanol. 1, 4. doi:10.1186/2191-5040-1-4
de Silva, S. (2008). Arc Magmatism, Calderas, and Supervolcanoes. Geology 36, 671–672. doi:10.1130/focus082008.1
de Silva, S. L., and Gregg, P. M. (2014). Thermomechanical Feedbacks in Magmatic Systems: Implications for Growth, Longevity, and Evolution of Large Caldera-Forming Magma Reservoirs and Their Supereruptions. J. Volcanol. Geotherm. Res. 282, 77–91. doi:10.1016/j.jvolgeores.2014.06.001
Deligne, N. I., Coles, S. G., and Sparks, R. S. J. (2010). Recurrence Rates of Large Explosive Volcanic Eruptions. J. Geophys. Res. Solid Earth 115. doi:10.1029/2009jb006554
Discovery Channel (1995). Supervolcano (Movie). Available at: https://www.imdb.com/title/tt0419372/.
Folch, A., and Marti, J. (2004). Geometrical and Mechanical Constraints on the Formation of Ring-Fault Calderas. Earth Planet. Sci. Lett. 221 (1–4), 215–255. doi:10.1016/s0012-821x(04)00101-3
Forbes.com (2021). Kerguelen Plateau is Earth's Longest Continuously Erupting Supervolcano. Available at: https://www.forbes.com/sites/davidbressan/2020/11/06/kerguelen-plateau-is-earths-longest-continuously-erupting-supervolcano/. (Accessed October 10, 2021).
Garcia, M. O., Tree, J. P., Wessel, P., and Smith, J. R. (2020). Pūhāhonu: Earth's Biggest and Hottest Shield Volcano. Earth Planet. Sci. Lett. 542, 116296. doi:10.1016/j.epsl.2020.116296
Geological Society of London (2013). What Really Happens in a Flood Basalt Eruption. Available at: https://blog.geolsoc.org.uk/2013/04/10/what-really-happens-in-a-flood-basalt-eruption/. (Accessed December 27, 2021).
Gregg, P. M., de Silva, S. L., Grosfils, E. B., and Parmigiani, J. P. (2012). Catastrophic Caldera-Forming Eruptions: Thermomechanics and Implications for Eruption Triggering and Maximum Caldera Dimensions on Earth. J. Volcanol. Geotherm. Res. 241-242, 1–12. doi:10.1016/j.jvolgeores.2012.06.009
Gregg, P. M., de Silva, S. L., and Grosfils, E. B. (2013). Thermomechanics of Shallow Magma Chamber Pressurization: Implications for the Assessment of Ground Deformation Data at Active Volcanoes. Earth Planet. Sci. Lett. 384, 100–108. doi:10.1016/j.epsl.2013.09.040
Gudmundsson, A. (1998). Formation and Development of Normal-Fault Calderas and the Initiation of Large Explosive Eruptions. Bull. Volcanol. 60, 160–170. doi:10.1007/s004450050224
Hogg, A., Lowe, D. J., Palmer, J., Boswijk, G., and Bronk Ramsey, C. (2011). Revised Calendar Date for the Taupo Eruption Derived by 14C Wiggle-Matching Using a New Zealand Kauri 14C Calibration Data Set. The Holocene 22 (4), 439–449. doi:10.1177/0959683611425551
Houghton, B. F., Carey, R. J., and Rosenberg, M. D. (2014). The 1800a Taupo Eruption: “III Wind” Blows the Ultraplinian Type Event Down to Plinian. Geology 42, 459–461. doi:10.1130/g35400.1
Jellinek, A. M., and DePaolo, D. J. (2003). A Model for the Origin of Large Silicic Magma Chambers: Precursors of Caldera-Forming Eruptions. Bull. Volcanol. 65, 363–381. doi:10.1007/s00445-003-0277-y
Karlstrom, L., Dufek, J., and Manga, M. (2010). Magma Chamber Stability in Arc and Continental Crust. J. Volcanol. Geotherm. Res. 190 (34), 249–270. doi:10.1016/j.jvolgeores.2009.10.003
Kennedy, B. M., Stix, J., Vallance, J. W., Lavallee, Y., and Longpre, M.-A. (2004). Controls on Caldera Structure: Results from Analogue Sandbox Modeling. Geol. Soc. Am. Bull. 116 (5/6), 515–524. doi:10.1130/b25228.1
Japanese Meteorological Agency (2021). “Global Volcanism Program, 2021. Report on Asosan (Japan),” in Weekly Volcanic Activity Report. Editor S. K. Sennert (Smithsonian Institution and US Geological Survey). Available at: https://volcano.si.edu/showreport.cfm?doi=GVP.WVAR20211117-282110. (Accessed November 17–23, 2021).
Japanese Meteorological Agency (2022). “Global Volcanism Program, 2022. Report on Aira (Japan),” in Weekly Volcanic Activity Report. Editor S. K. Sennert (Smithsonian Institution and US Geological Survey). Available at: https://volcano.si.edu/showreport.cfm?doi=GVP.WVAR20220105-282080. (Accessed January 5–11, 2022).
Kutterolf, S., Schindlbeck, J., Anselmetti, F., Ariztegui, D., Brenner, M., Curtis, J., et al. (2016). A 400-ka Tephrochronological Framework for Central America from Lake Petén Itzá (Guatemala) Sediments. Quat. Sci. Rev. 150, 200–220.
Lipman, P. W. (1997). Subsidence of Ash-Flow Calderas: Relation to Caldera Size and Magma-Chamber Geometry. Bull. Volcanol. 59, 198–218. doi:10.1007/s004450050186
Lowenstern, J. B., Smith, R. B., and Hill, D. P. (2006). Monitoring Super-Volcanoes: Geophysical and Geochemical Signals at Yellowstone and Other Large Caldera Systems. Phil. Trans. Roy. Soc. A. 364, 2055–2072. doi:10.1098/rsta.2006.1813
Maeno, F., and Taniguchi, H. (2007). Spatiotemporal Evolution of a Marine Caldera-Forming Eruption, Generating a Low-Aspect Ratio Pyroclastic Flow, 7.3 Ka, Kikai Caldera, Japan: Implication from Near-Vent Eruptive Deposits. J. Volcanol. Geotherm. Res. 167, 212–238. doi:10.1016/j.jvolgeores.2007.05.003
Mark, D. F., Petraglia, M., Smith, V. C., Morgan, L. E., Barfod, D. N., Ellis, B. S., et al. (2014). A High-Precision 40Ar/39Ar Age for the Young Toba Tuff and Dating of Ultra-Distal Tephra: Forcing of Quaternary Climate and Implications for Hominin Occupation of India. Quat. Geochronol. 21, 90–103.
Mason, B. G., Pyle, D. M., and Oppenheimer, C. (2004). The Size and Frequency of the Largest Explosive Eruptions on Earth. Bull. Volcanol. 66, 735–748. doi:10.1007/s00445-004-0355-9
Matsumoto, A., and Ui, T. (1997). K-ar Age of Ata Pyroclastic Flow Deposit, Southern Kyushu, Japan. Bull. Volcanol. Soc. Jpn. 42, 223
Matthews, N. E., Vazquez, J. A., and Calvert, A. T. (2015). Age of the Lava Creek Supereruption and Magma Chamber Assembly at Yellowstone Based on 40Ar/39Ar and U-Pb Dating of Sanidine and Zircon Crystals. Geochem. Geophys. Geosyst. 16, 2508–2528. doi:10.1002/2015gc005881
Miller, C. F., and Wark, D. A. (2008). Supervolcanoes and Their Explosive Supereruptions. Elements 4, 11–15. doi:10.2113/gselements.4.1.11
Morgan, L. E., Johnstone, S. A., Gilmer, A. K., Cosca, M. A., and Thompson, R. A. (2020). A Supervolcano and its Sidekicks: A 100 Ka Eruptive Chronology of the Fish Canyon Tuff and Associated Units of the La Garita Magmatic System, Colorado, USA. Geology 47, 453–456. doi:10.1353/col.2020.0040
Mucek, A. E., Danišík, M., de Silva, S. L., Miggins, D. P., Schmitt, A. K., Pratomo, I., et al. (2021). Resurgence Initiation and Subsolidus Eruption of Cold Carapace of Warm Magma at Toba Caldera, Sumatra. Commun. Earth Environ. 2, 185. doi:10.1038/s43247-021-00260-1
Mucek, A. E., Danišík, M., de Silva, S. L., Miggins, D. P., Schmitt, A. K., Pratomo, I., et al. (2017). Post-Supereruption Recovery at Toba Caldera. Nat. Commun. 8, 15248. doi:10.1038/ncomms15248
Newhall, C. G., and Self, S. (1982). The Volcanic Explosivity Index (VEI) an Estimate of Explosive Magnitude for Historical Volcanism. J. Geophys. Res. 87, 1231–1238. doi:10.1029/jc087ic02p01231
Newhall, C., Self, S., and Robock, A. (2018). Anticipating Future Volcanic Explosivity Index (VEI) 7 Eruptions and Their Chilling Impacts. Geosphere 14, 572–603. doi:10.1130/ges01513.1
Parfitt, E. A. (2004). A Discussion of the Mechanisms of Explosive Basaltic Eruptions. J. Volcanol. Geotherm. Res. 134, 77–107. doi:10.1016/j.jvolgeores.2004.01.002
Poland, M. (2019). A Personal Commentary: Why I Dislike the Term “Supervolcano” (And What We Should Be Saying Instead). Available at: https://www.usgs.gov/news/personal-commentary-why-i-dislike-term-supervolcano-and-what-we-should-be-saying-instead. (Accessed January 22, 2022).
Pyle, D. M. (1998). Forecasting Sizes and Repose Times of Future Extreme Volcanic Events. Geology 26, 367–370. doi:10.1130/0091-7613(1998)026<0367:fsarto>2.3.co;2
Pyle, D. M. (1995). Mass and Energy Budgets of Explosive Volcanic Eruptions. Geophys. Res. Lett. 22, p563–566. doi:10.1029/95gl00052
Pyle, D. M. (2000). “The Sizes of Volcanic Eruptions,” in Encyclopedia of Volcanoes. Editors H. Sigurdsson, B. Houghton, S. R. McNutt, H. Rymer, and J. Stix, (London, UK: Academic Press), 263–269.
Rampino, M. R., and Self, S. (1992). Volcanic Winter and Accelerated Glaciation Following the Toba Super-Eruption. Nature 359, 50–52. doi:10.1038/359050a0
Reidel, S. P., Camp, V. C., Ross, M. E., Wolff, J. A., Martin, B. S., and Tolan, T. L. (2013). The Columbia River Basalt Province. Geological Society of America Special Paper 497, 440.
Rose, W. I., and Chesner, C. A. (1987). Dispersal of Ash in the Great Toba Eruption, 75 Ka. Geology 15, 913–917. doi:10.1130/0091-7613(1987)15<913:doaitg>2.0.co;2
Rose, W. I., Conway, F. M., Pullinger, C. R., Deino, A., and McIntosh, W. C. (1999). Improved Age Framework for Late Quaternary Silicic Eruptions in Northern Central America. Bull. Volcanol. 61 (1-2), 106–120. doi:10.1007/s004450050266
Sager, W. W., Zhang, J., Korenaga, J., Sano, T., Koppers, A. P., Widdowson, M., et al. (2013). An Immense Shield Volcano within the Shatsky Rise Oceanic Plateau, Northwest Pacific Ocean. Nat. Geosci. 6, 1934. doi:10.1038/ngeo1934
Scandone, R., and Acocella, V. (2007). Control of the Aspect Ratio of the Chamber Roof on Caldera Formation During Silicic Eruptions. Geophys. Res. Lett. 34, L22307. doi:10.1029/2007gl032059
Self, S., Jay, A. E., Widdowson, M., and Keszthelyi, L. P. (2008). Correlation of the Deccan and Rajahmundry Trap Lavas: Are These the Longest and Largest Lava Flows on Earth? J. Volcanol. Geotherm. Res. 172, 3–19. doi:10.1016/j.jvolgeores.2006.11.012
Self, S., Keszthelyi, L. P., and Thordarsson, Th. (1998). The Importance of Pahoehoe. Annu. Rev. Earth Planet. Sci. 26, 81–110. doi:10.1146/annurev.earth.26.1.81
Self, S., Schmidt, A., and Mather, T. A. (2014). Emplacement Characteristics, Time Scales, and Volcanic Gas Release Rates of Continental Flood Basalt Eruptions on Earth, in Keller, G., and Kerr, A.C., eds., Volcanism, Impacts, and Mass Extinctions: Causes and Effects: Geological Society of America Special Paper 505, p. 319–337. doi:10.1130/2014.2505(16)
Self, S. (2006). The Effects and Consequences of Very Large Explosive Volcanic Eruptions. Philos. Trans. R. Soc. A. 364, 2073–2097. doi:10.1098/rsta.2006.1814
Silleni, A., Giordano, G., Isaia, R., and Ort, M. H. (2020). The Magnitude of the 39.8 Ka Campanian Ignimbrite Eruption, Italy: Method, Uncertainties and Errors. Front. Earth Sci. 8, 543399. doi:10.3389/feart.2020.543399
Smith, R. L. (1979). Ash Flow Magmatism. Geological Society of America Special Paper 180, 5–28. doi:10.1130/spe180-p5
Smith, R. L., and Bailey, R. A. (1968). “Resurgent Cauldrons,” in Studies in Volcanology. Editors R. R. Coats, R. L. Hay, and C. A. Anderson. (Geological Society of America Memoirs), 116, 613–662. doi:10.1130/mem116-p613
Sparks, R. S. J., Francis, P. W., Hamer, R. D., Pankhurst, R. J., O'Callaghan, L. O., Thorpe, R. S., et al. (1985). Ignimbrites of the Cerro Galan Caldera, NW Argentina. J. Volcanol. Geotherm. Res. 24, 205–248. doi:10.1016/0377-0273(85)90071-x
Sparks, R. S. J., Self, S., Grattan, J. P., Oppenheimer, C., Pyle, D. M., and Rymer, H. (2005). Super-Eruptions: Global Effects and Future Threats. London: Report of a Geological Society of London Working Group, The Geological Society, 24.
Spera, F. J., and Crisp, J. A. (1981). Eruption Volume, Periodicity, and Caldera Area: Relationships and Inferences on Development of Compositional Zonation in Silicic Magma Chambers. J. Volcanol. Geotherm. Res. 11, 169–187. doi:10.1016/0377-0273(81)90021-4
Stokke, E., Liu, E., and Jones, M. (2020). Evidence of Explosive Hydromagmatic Eruptions During the Emplacement of the North Atlantic Igneous Province. Volcanica 3 (2), 227–250. doi:10.30909/vol.03.02.227250
Storey, M., Roberts, R. G., and Saidin, M. (2012). Astronomically Calibrated 40Ar/39Ar Age for the Toba Supereruption and Global Synchronization of Late Quaternary Records. Proc. Natl. Acad. Sci. USA. 109, 18684–18688. doi:10.1073/pnas.1208178109
Takarada, S., and Hoshizumi, H. (2020). Distribution and Eruptive Volume of Aso-4 Pyroclastic Density Current and Tephra Fall Deposits, Japan: A M8 Super-Eruption. Front. Earth Sci. 8, 170. doi:10.3389/feart.2020.00170
Tatsumi, Y., Suzuki-Kamata, K., Matsuno, T., Ichihara, H., Seama, N., Kiyosugi, K., et al. (2018). Giant Rhyolite Lava Dome Formation after 7.3 Ka Supereruption at Kikai Caldera, SW Japan. Sci. Rep. 8, 2753. doi:10.1038/s41598-018-21066-w
Tolan, T. L., Reidel, S. P., Beeson, M. H., Anderson, J. L., Fecht, K. R., and Swanson, D. A. (1989). Revisions to the Estimates of the Areal Extent and Volume of the Columbia River Basalt Group, in Reidel, S. P., and Hooper, P. R., eds., Volcanism and Tectonism in the Columbia River Flood-Basalt Province: Boulder, Colorado, Geological Society of America, Special Paper 239. p.1-20
Torres, R. C., Self, S., and Punongbayan, R. S. (1995). Attention Focuses on Taal: Decade Volcano of the Philippines. Eos Trans. AGU 76, 241. Eos Transactions of the American Geophysical Union. doi:10.1029/95eo00137
United States Geological Survey (2022a). Long Valley. Available at: https://www.usgs.gov/volcanoes/long-valley-caldera. (Accessed January 05, 2022).
United States Geological Survey (2022b). Questions About Supervolcanoes. Available at: https://www.usgs.gov/volcanoes/yellowstone/questions-about-supervolcanoes. (Accessed January 05, 2022).
Vandergoes, M. J., Hogg, A. G., Lowe, D. J., Newnham, R. M., Denton, G. H., Southon, J., et al. (2013). A Revised Age for the Kawakawa/Oruanui Tephra, a Key Marker for the Last Glacial Maximum in New Zealand. Quat. Sci. Rev. 74, 195–201. doi:10.1016/j.quascirev.2012.11.006
Walker, G. P. L. (1980). The Taupo Pumice: Product of the Most Powerful Known (Ultraplinian) Eruption? J. Volcanol. Geotherm. Res. 8, 69–94. doi:10.1016/0377-0273(80)90008-6
Watts, K. E., Bindeman, I. N., and Schmitt, A. K. (2012). Crystal Scale Anatomy of a Dying Supervolcano: An Isotope and Geochronology Study of Individual Phenocrysts from Voluminous Rhyolites of the Yellowstone Caldera. Contrib. Mineral. Petrol. 164, 45–67. doi:10.1007/s00410-012-0724-x
Wikipedia (2021). Supervolcano. Available at: https://en.wikipedia.org/wiki/Supervolcano. (Accessed October 24, 2021).
Wilson, C. J. N. (2001). The 26.5 Ka Oruanui Eruption, New Zealand: An Introduction and Overview. J. Volcanol. Geotherm. Res. 112, 133–174. doi:10.1016/s0377-0273(01)00239-6
Zielinski, G. A., Mayewski, P. A., Meeker, L. D., Whitlow, S., Twickler, M. S., and Taylor, K. (1996). Potential Atmospheric Impact of the Toba Mega-Eruption ∼71,000 Years Ago. Geophys. Res. Lett. 23, 837–840. doi:10.1029/96gl00706
Keywords: supervolcano, supereruption, VEI, magnitude scale, calderas
Citation: de Silva S and Self S (2022) Capturing the Extreme in Volcanology: The Case for the Term “Supervolcano”. Front. Earth Sci. 10:859237. doi: 10.3389/feart.2022.859237
Received: 21 January 2022; Accepted: 21 March 2022;
Published: 05 May 2022.
Edited by:
Valerio Acocella, Roma Tre University, ItalyReviewed by:
James Cole, University of Canterbury, New ZealandPaolo Papale, Istituto Nazionale di Geofisica e Vulcanologia (INGV), Italy
Copyright © 2022 de Silva and Self. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Shanaka de Silva, desilvsh@oregonstate.edu