Kurzgesagt – In a Nutshell
Thanks to our experts —
Dr. James Hickey
University of Exeter
Dr. Mike Cassidy
University of Oxford
Sources – Supervolcanoes
– The Earth is a gigantic ball of semi-molten rock, with a heart of iron as hot as the surface of the Sun.
The Earth’s core is a huge sphere made mostly of iron with two parts: the outer core, which is liquid; and the inner core, which (maybe somewhat unexpectedly) is solid due to the enormous pressure. The exact temperature at the very center of the Earth is uncertain. However, the temperature at the inner-outer core boundary (i.e. where the core melts) should be close to the melting temperature of iron at 330 gigapascal, the calculated pressure in that region. In 2013, researchers estimated that temperature to be between 5730 and 6730 kelvin. The surface temperature of the Sun reaches almost 5800 kelvin.
#Anzellini, S. et al. (2013): Melting of Iron at Earth's Inner Core Boundary Based on Fast X-ray Diffraction. Science, Vol. 340 (6131)
Quote: "The temperature at the inner core boundary is expected to be close to the melting point of iron at 330 gigapascal (GPa). We present static laser-heated diamond anvil cell experiments up to 200 GPa using synchrotron-based fast x-ray diffraction as a primary melting diagnostic. When extrapolating to higher pressures, We conclude that the melting temperature of iron at the inner core boundary is 6230 ± 500 kelvin."
– Titanic amounts of heat left over from its birth and the radioactive decay of trillions of tons of radioactive elements find no escape but up. Currents of partially molten rock spanning thousands of kilometers carry this energy to the surface.
#Lay, T. et al. (2008): Core–mantle boundary heat flow. Nature Geoscience, Vol. 1
https://www.geol.umd.edu/~mcdonoug/KITP%20Website%20for%20Bill/papers/Earth_Models/Lay_etal_(NatureG_08).pdf
Quote: “The current total heat flow at the Earth’s surface — 46 ± 3 terawatts (1012 J s–1) — involves contributions from heat entering the mantle from the core, as well as mantle cooling, radiogenic heating of the mantle from the decay of radioactive elements, and various minor processes such as tidal deformation, chemical segregation and thermal contraction gravitational heating.”
The average concentration of Uranium (one of the main sources of radiogenic heat) in the Earth’s crust amounts to several parts per million:
#World Nuclear Association (2022): Supply of Uranium
https://world-nuclear.org/information-library/nuclear-fuel-cycle/uranium-resources/supply-of-uranium.aspx
And the mass of the crust has been estimated to be of the order of 1022 kg:
#Peterson, B. T. & Depaolo, D. J. (2007): Mass and Composition of the Continental Crust Estimated Using the CRUST2.0 Model. American Geophysical Union, Fall Meeting 2007.
https://ui.adsabs.harvard.edu/abs/2007AGUFM.V33A1161P/abstract
Quote: “The ultimate constraint is the total mass of Earth's crust (oceanic + continental), which, from C2, is 2.77 (in units of 1022 kg).”
This gives an amount of Uranium in the crust of the order of 1019 * 10(-6) = 1013 metric tons, i.e. (tens of) trillions of metric tons.
The concentration of Uranium in the mantle is known to be much lower than in the crust, but the mantle is also much bigger. In 2020, researchers estimated the amount of radiogenic heat generated in the Earth’s mantle by measuring the flux of neutrinos, and found it to be of the same order of magnitude (dozens of TW) as the total heat flux at the surface:
#Borexino Collaboration (2020): Comprehensive geoneutrino analysis with Borexino. Physical Review D 101
https://journals.aps.org/prd/pdf/10.1103/PhysRevD.101.012009
Quote: “Measured mantle signal of [...] corresponds to the production of a radiogenic heat of [24 TW] from 238 U and 232 Th in the mantle.”
– Earth’s crust is the only thing in their way. It feels solid to us, but it is only a fragile barrier, an apple skin around a flaming behemoth.
The Earth’s crust represents a 5 to 30 km layer of rock floating on a sphere of molten or semi-molten material extending 6371 km down to the center. That makes it 0.08% to 0.5% as thick as the Earth’s radius.
#NASA (2022): Earth. Our Home Planet
https://solarsystem.nasa.gov/planets/earth/in-depth/#otp_structure
Quote: “Earth is composed of four main layers, starting with an inner core at the planet's center, enveloped by the outer core, mantle, and crust.
The inner core is a solid sphere made of iron and nickel metals about 759 miles (1,221 kilometers) in radius. There the temperature is as high as 9,800 degrees Fahrenheit (5,400 degrees Celsius). Surrounding the inner core is the outer core. This layer is about 1,400 miles (2,300 kilometers) thick, made of iron and nickel fluids.
In between the outer core and crust is the mantle, the thickest layer. This hot, viscous mixture of molten rock is about 1,800 miles (2,900 kilometers) thick and has the consistency of caramel. The outermost layer, Earth's crust, goes about 19 miles (30 kilometers) deep on average on land. At the bottom of the ocean, the crust is thinner and extends about 3 miles (5 kilometers) from the seafloor to the top of the mantle.”
For comparison, an apple skin is between 0.03 and 0.07 mm thick, with a typical fruit radius of 4 or 5 cm, which gives a similar ratio of the order of 0.1%
#Homutová, I. & Blažek, J. (2006): Differences in fruit skin thickness between selected apple (Malus domestica Borkh.) cultivars assessed by histological and sensory methods. Horticultural Science, Vol. 33 (3)
https://www.agriculturejournals.cz/publicFiles/51351.pdf
Quote: “In total 20 grown cultivars and advanced selections were included in a two-year study of apple skin thickness. The mean skin thickness of single cultivars measured on classical histological sections through the skin varied from 33.3 μm to 73.1 μm”
– True apocalypses can break through and unleash eruptions ten of times more powerful than all of our nuclear weapons combined, subjecting the climate to centuries worth of change in a single year, while drowning continents in toxic ash and gases: supervolcanoes. How big can they get? Will they end humanity and could we stop them?
As it will be shown below, the most powerful eruptions in the geological record typically released an explosive power equivalent to dozens of billions of tonnes of TNT. And as we explained in this video:
#Kurzgesagt (2019): What If We Detonated All Nuclear Bombs at Once?
https://www.youtube.com/watch?v=JyECrGp-Sw8
All the nuclear bombs combined have an estimated power of about 3 billion tons of TNT. The calculation is explained in the sources of the video:
#Kurzgesagt (2019): Sources – All the bombs.
https://sites.google.com/view/sourcesallthebombs/
– There are many types of volcanos, from towering mountains to lava domes, but they have two main sources:
This page lists 6 types of volcanoes with four different potential landforms for each one.
#National Park Service (2022): Types of Volcanoes
https://www.nps.gov/subjects/volcanoes/types-of-volcanoes.htm
– The first is at the boundaries between tectonic plates, the pieces of the crust that cover the Earth like a giant jigsaw puzzle. There are seven major tectonic plates and dozens of smaller ones, drifting against each other at up to 15 cm per year. This sounds slow, but on geological timescales it is a titanic struggle over who gets to stay on the surface. The winning plate crumples into a new mountain range while the loser is shoved underneath, into an ocean of rock around 1300°C hot: The asthenosphere.
Tectonic activity such as earthquakes are caused by the motion of seven major tectonic plates.
#Encyclopaedia Britannica (2022): Plate tectonics
https://www.britannica.com/science/plate-tectonics
Quote: “The lithosphere is broken up into seven very large continental- and ocean-sized plates, six or seven medium-sized regional plates, and several small ones. These plates move relative to each other, typically at rates of 5 to 10 cm (2 to 4 inches) per year, and interact along their boundaries, where they converge, diverge, or slip past one another. Such interactions are thought to be responsible for most of Earth’s seismic and volcanic activity, although earthquakes and volcanoes can occur in plate interiors.”
The fastest plate motion is reported to take place in the Pacific Ocean, near Easter Island, at a rate of more than 15 cm/year.
#USGS (2014): Understanding plate motions
https://pubs.usgs.gov/gip/dynamic/understanding.html
Quote: “The Arctic Ridge has the slowest rate (less than 2.5 cm/yr), and the East Pacific Rise near Easter Island, in the South Pacific about 3,400 km west of Chile, has the fastest rate (more than 15 cm/yr).”
Subduction is one of the more violent interactions between tectonic plates
#USGS (2020): Introduction to Subduction Zones
#SDSU College of Sciences (retrieved 2022): How Volcanoes Work. Subduction Zone Volcanism
http://sci.sdsu.edu/how_volcanoes_work/subducvolc_page.html
Quote: “Subduction zone volcanism occurs where two plates are converging on one another. One plate containing oceanic lithosphere descends beneath the adjacent plate, thus consuming the oceanic lithosphere into the earth's mantle. This on-going process is called subduction. As the descending plate bends downward at the surface, it creates a large linear depression called an oceanic trench. These trenches are the deepest topographic features on the earth's surface. The deepest, 11 kilometers below sea level, is the Mariana trench, which lies along the western margin of the Ring of Fire.”
And this all happens over a ductile layer of rock and semi-molten material between the crust and upper mantle of the Earth called the asthenosphere.
#Geological Society of London (retrieved 2022): The Crust and Lithosphere
Quote: "The weaker mechanical properties of the asthenosphere are attributable to the fact that, within this part of the upper mantle, temperatures lie close to the melting temperature (with localised partial melting giving rise to magma generation). The base of the lithosphere is conventionally defined as the 1300 C isotherm since mantle rocks below this temperature are sufficiently cool to behave in a rigid manner."
– The temperature here is enough to melt rock into a liquid, but the insane pressures of all that mass keep it a superheated solid. Tectonic plates are usually in contact with water for thousands of years and absorb some of it. When they are submerged into the hot underworld, this water triggers chemical transformations that allow tiny portions to melt into magma. Liquid magma is less dense than solid rock, so it rises to the surface in furious bubbles that accumulate in sponge-like reservoirs right under the crust.
Adding water to the asthenosphere causes chemical changes that trigger the melting of rock despite the intense pressures that normally prevents it from happening. The process is explained in the following passages:
#Tanner, L. H. & Calvar, S. (2008): Volcanoes: Windows on the Earth. New Mexico Museum of Natural History & Science
https://www.researchgate.net/publication/230752425_Volcanoes_Windows_on_the_Earth
Quote: “In general, however, we may say that the temperatures required to form any significant volumes of magma are not reached under average conditions in the mantle due to the great pressure. Therefore, magma formation must take place under some conditions that differ from the average.
[...]
Water, in the form of water vapor, acts as a flux, lowering the melting point of the minerals in rocks. At the surface, this property has little effect on the melting point of rocks, but at great depth (high temperatures and pressures), the presence of the water molecules weakens the
chemical bonds in the mineral grains and lowers the melting temperature. The result is a decrease in the melting point of rock with increasing depth, the opposite of what
we see in the absence of water.
[...]
For example, at a pressure of 25 kilobars, corresponding to a depth of about 75 kilometers
(47 miles), dry basalt melts at a temperature of nearly 1400°C (2550° F), but in the presence of water, the melting point drops to around 800° C (1470° F).”
The liberated magma then starts to rise to the surface as it is less dense than its surroundings. However, its journey to the surface is not a straight line. It can be trapped in vast reservoirs, themselves containing multiple levels and chambers. Within these chambers, the magma can solidify again, undergo chemical changes, release gases or melt once more.
#Sparks, R. S. J. et al. (2019): Formation and dynamics of magma reservoirs. Philosophical Transactions of the Royal Society A, Vol. 377 (2139)
https://royalsocietypublishing.org/doi/10.1098/rsta.2018.0019
Quote: “We define a magma reservoir as the domains within the magmatic system that contain melt (±fluid) and by definition are above the solidus. In some mature systems, there may be one continuous, interconnected domain (reservoir) from the mantle into the shallow crust while in other systems there may be multiple domains (reservoirs) separated by zones of completely solid (melt-free) rock (figure 2). We acknowledge that it is common in the literature to regard the terms magma chamber and magma reservoir as synonymous, but this is increasingly problematic because of the recognition that melts distributed at a small scale within largely crystalline rock may under some circumstances be rapidly extracted ”
– If enough magma accumulates, it becomes powerful enough to pierce through the crust – which we experience as volcanoes. This happens under the winning plate, like a revenge attack by the loser before it is erased forever.
A certain threshold pressure is needed to break through the rocks surrounding the magma reservoirs. This is apparently equal to at least twice the strength of those rocks.
#Tait, S. et al. (1989): Pressure, gas content and eruption periodicity of a shallow, crystallising magma chamber. Earth and Planetary Science Letters, Vol. (92) 1
https://www.sciencedirect.com/science/article/abs/pii/0012821X89900253
Quote: “We calculate the overpressure in the chamber and consequent increase in its volume by deformation of the surrounding rocks as a function of the amount of crystallisation. When the overpressure reaches a value of twice the effective tensile strength of the volcanic edifice, eruption or emplacement of a dyke occurs, and the chamber returns to its original pressure and volume.”
– The second main source of volcanoes are thought to be mantle plumes. These are columns of abnormally hot magma that rise all the way from the planet’s core-mantle boundary to the surface. Much less is known about them, but in a way it is as if the Earth’s mantle has climate patterns and mantle plumes are a little like hot air rising to form storm clouds. Storms hundreds of millions of years old, made of rock circulating at a rate of a few millimetres per month. They don’t care about the motion of tectonic plates, so they can break the crust to create volcanoes in the middle of nowhere that stubbornly stay active as the crust shifts around them.
#Choi, C. (2013): Mantle plumes. Proceedings of the National Academy of Sciences, Vol. 110 (7)
https://www.pnas.org/doi/10.1073/pnas.1300192110
Quote: “Volcanoes are usually found near the borders of tectonic plates that are violently either pushing or pulling at each other. Mysteriously, however, volcanoes sometimes erupt in the middle of these plates instead. The culprits behind these outbursts might be giant pillars of hot molten rock known as mantle plumes, jets of magma rising up from near the Earth’s core to penetrate overlying material like a blowtorch. Still, decades after mantle plumes were first proposed, controversy remains as to whether or not they exist.”
The following diagram shows how mantle plumes rise all the way from the Earth’s core, and are replenished by material falling from the surface.
#Sleep, N. H. (2006): Mantle plumes from top to bottom. Earth-Science Reviews, Vol. 77 (4)
https://geosci.uchicago.edu/~archer/deep_earth_readings/sleep.2006.plumes_rev.pdf
Each mantle plume has a different velocity but a few cm per year is typical, which translates to about 1 mm per month.
#Steinberger, B. & Antretter, M. (2006): Conduit diameter and buoyant rising speed of mantle plumes: Implications for the motion of hot spots and shape of plume conduits. Geochemistry, Geophysics, Geosystems, Vol. 7 (11)
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2006GC001409
Volcanic “hotspots” (active volcanic regions that are independent of tectonic plate boundaries), like the Hawaii chain of volcanoes, are powered by mantle plumes.
#DePaolo, D. J. & Manga, M. (2003): Deep Origin of Hotspots - the Mantle Plume Model. Science, Vol. 300 (5621)
http://www.mantleplumes.org/WebDocuments/DePaoloPerspectives.pdf
Quote: “But not all volcanoes on Earth are located at mid-ocean ridges or subduction
zones. “Hotspots”—regions with particularly high rates of volcanism—are not necessarily associated with plate boundaries. Hawaii, the premier example, is thousands of kilometers from the nearest plate boundary yet exudes lava at a higher rate per unit area than at any other place on Earth. The Hawaiian volcanic anomaly has remained mostly stationary for tens of millions of years and produced a 6000-km-long chain of islands and seamounts. This phenomenon is not explained by plate tectonics. It requires a separate mantle process that can account for narrow, long-lived upwellings of unusually hot mantle rock.”
– Scientists love to put big booms on a scale and came up with a logarithmic scale that measures the volume ejected during an eruption: The Volcanic Explosivity Index, or VEI. Simply put, it starts really small and gets very big very quickly.
#National Park Service (2022): Volcanic Explosivity Index (VEI)
https://www.nps.gov/subjects/volcanoes/volcanic-explosivity-index.htm
Quote: “The Volcanic Explosivity Index (VEI) is a scale that describes the size of explosive volcanic eruptions based on magnitude and intensity. The numerical scale (from 0 to 8) is a logarithmic scale, and is generally analogous to the Richter and other magnitude scales for the size of earthquakes.”
The scale was introduced in 1982 by Christopher Newhall and Stephen Self:
#Newhall, C. G. & Self, S. (1982): The Volcanic Explosivity Index (VEI):
An Estimate of Explosive Magnitude for Historical Volcanism. Journal of Geophysical Research, Vol. 87 (C2).
Apart from referring to the volume of ejected material, the VEI-number also encapsulates other features of an eruption, like the height of the eruptive column or the amount of material injected in the stratosphere or the troposphere. The VEI-number is also related to the duration of continuous blast, which can vary from a few hours (in the case of lower VEI) to days (higher VEI).
The Wikipedia entry on the Volcanic Explosivity Index has a neat table for reference.
#Wikipedia (retrieved 2022): Volcanic Explosivity Index
– A VEI 2 eruption would fill four hundred full Olympic swimming pools with lava. We have around 10 of these per year.
A VEI 2 eruption has a typical volume of about 1,000,000 m3 of “tephra” (the technical term for the ejected materials–basically lava and fragmented lava). This is equivalent to 400 Olympic swimming pools, which have an official volume of 2500 m3.
A very clear table of the frequency of the different VEI-eruptions can be found in Figure 2 of the following article:
#Rampino, M. (2002): Supereruptions as a Threat to Civilizations on Earth-like Planets. Icarus, Vol. 156 (2)
Quote: “Plot of magnitude versus frequency for volcanic eruptions (VEI classes 2 to 8). Total number of eruptions during various intervals (going back in timefrom 1 January 1994) for each VEI class is normalized to eruptions per 1000 years. Tephra volumes corresponding to each VEI class are shown at top. The best-fitline was determined by a regression model using the filled data points. Data points from Decker (1990) for VEI 7 and 8 are shown by open triangles (after Simkinand Siebert 1994).”
– At VEI 3 we already see devastating effects, like the eruption of the Semeru volcano in 2021 that destroyed thousands of homes in Indonesia.
A VEI 3 eruption has a volume of over 10,000,000 m3. This is enough to fill twenty times the Hellespont Alhambra oil tanker, which belongs to the largest Ultra Large Crude Carrier class.
#Wärtsilä (retrieved 2022): Ultra large crude carrier HELLESPONT ALHAMBRA https://www.wartsila.com/encyclopedia/term/ultra-large-crude-carrier-hellespont-alhambra
Quote: “Length, oa:380.00m, Length, bp: 366.00m, Beam: 68.00m, Depth, moulded: 34.00m, Draught scantling: 24.50m, Deadweight scantling: 442,470dwt, Lightweight: 67,000t, Cargo capacity: 513,684m3, Main engine: Wärtsilä Sulzer 9RTA84T-D, Output, MCR at 76 rev/min: 36,900kW, Speed, loaded 95%MCR, 15% sea margin:16.5 knots, Speed in ballast:17.9 knots, Main engine fuel consumption:141t/day.”
The 2021 eruption of Mount Semeru produced an ash plume of about 15 km, the height associated to VEI 3 eruptions:
#Global Volcanism Program (2022): Report on Semeru (Indonesia), Bulletin of the Global Volcanism Network, Vol. 47 (1)
https://volcano.si.edu/showreport.cfm?doi=10.5479/si.GVP.BGVN202201-263300
Quote: “An eruption and dome collapse near the summit on 4 December 2021, during several days of heavy rain, produced a 15-km-high ash plume and pyroclastic flows that inundated the Kobokan ravine and flowed into the Kobokan River, generating major lahars. Pyroclastic flows traveled up to 4 km from the summit, and lahars traveled more than 13 km, partially burying several communities and resulting in fatalities and significant damage.”
– At VEI 5, we see catastrophic amounts of materials, cubic kilometers of debris, equivalent to an entire lake of molten rock blasted into the air. Like the 2022 Hunga Tonga-Hunga Ha’apai eruption that sent a shockwave around the globe many times and created ocean-wide tsunamis.
A cubic kilometer is equal to one billion cubic meters. Here is a list of the 46 largest German lakes by volume:
#Schultze, M. et al. (2010): Introduction of river water as a tool to manage water quality in pit lakes. IMWA Annual Conference 2005
We find that Lake Schwerin is almost exactly 1000 million m3, or one cubic kilometer in volume. It is a sizeable lake!
The 2022 Hunga Tonga-Hunga Ha’apai eruption is estimated to be of this size.
#Yuen, D. A. et al. (2022): Under the surface: Pressure-induced planetary-scale waves, volcanic lightning, and gaseous clouds caused by the submarine eruption of Hunga Tonga-Hunga Ha'apai volcano. Earthquake Research Advances, Vol. 2 (3)
https://www.sciencedirect.com/science/article/pii/S2772467022000227
Quote: “The first hour of eruptive activity produced fast-propagating tsunami waves, long-period seismic waves, loud audible sound waves, infrasonic waves, exceptionally intense volcanic lightning and an unsteady volcanic plume that transiently reached—at 58 km—the Earth's mesosphere. [...] For an eruption duration of ∼12 h, the eruptive volume and mass are estimated at 1.9 km3 and ∼2 900 Tg, respectively, corresponding to a VEI of 5–6 for this event.”
#PBS News Hour (2022): Experts explain why Tonga eruption was so big
https://www.pbs.org/newshour/science/experts-explain-why-tonga-eruption-was-so-big
Quote: “The eruption on Saturday was incredibly explosive but also relatively brief. The plume rose into the air more than 30 kilometers (19 miles) but the eruption lasted only about 10 minutes, unlike some big eruptions that can continue for hours. Cronin said the power of the eruption of the Hunga Tonga Hunga Ha’apai volcano ranks among the world’s biggest over the past 30 years, and the height of the plume of ash, steam and gas was comparable with the huge 1991 eruption of Mount Pinatubo in the Philippines, which killed several hundred people.”
– At a VEI of 6, an eruption can change the world. In 1883, the Indonesian island volcano Krakatoa erupted nearly continuously over the course of 5 months. One of those eruptions blew it apart, producing the loudest sound recorded in history, 10 trillion times louder than a rocket taking off, heard halfway around the world. 30m high tsunamis swept away nearby populations and so much gas and ash were released that global temperatures cooled by nearly 0.5°C. Red dusty sunsets followed for many years.
Having occurred in the recent past, the properties of the 1883 Krakatoa eruption (loudness, ensuing tsunami and devastation) have been well documented:
#Bhattacharyya, A. & Hunter, G. (2020): A study of the Damaging Effects of Acoustic Shock Waves from a “Controlled” Explosion on Nearby Buildings. Proceedings of the Institute of Acoustics, Vol. 42 (1)
Quote: “In the historical fairly recent past, the explosive eruption of Krakatoa (or Krakatau) in modern Indonesia in 1883 was both devastating and well-documented (e.g. Verbeek 1884, Symons 1888, Thornton 1997), and generated sounds estimated at about 310 dB at source – loud enough to be heard in Perth, Western Australia (3110 km away) and the Indian Ocean island of Rodrigues near Mauritius (4800 km away) - plus a supersonic pressure wave, tsunamis and dust clouds which temporarily affected climatic conditions around the World.”
#NOAA (retrieved 2022): Tsunami Event Information Reference #237
https://www.ngdc.noaa.gov/hazel/view/hazards/tsunami/event-more-info/1142
Quote: “The explosion of the Krakatau Volcano in Indonesia generated a 30-m tsunami in the Sundra Strait that destroyed numerous towns and killed about 36,000 people. The explosion was heard about 3,000 miles away. ”
A rocket launch is measured at 180 decibels. This means it is 130 decibels weaker than the Krakatoa eruption. We can use the equation in the following source to calculate that 130 decibels translates into a power level 1013 times higher, which is ten trillion.
#ARRL (retrieved 2022): A Tutorial on the Decibel
And the event had a noticeable effect on global temperatures:
#Bradley, R. S. (1988): The explosive volcanic eruption signal in northern hemisphere continental temperature records. Climatic Change, Vol. 12 (3)
http://www.geo.umass.edu/faculty/bradley/bradley1988.pdf
Quote: “Very large, but historically rare, explosive eruptions (VEI 5 or 6) have a very pronounced, short-lived impact on continental surface temperature. [...] Over northern hemisphere land areas as a whole, initial temperature depression averages 0.4 ºC.”
And also remarkable optical effects:
#NASA (retrieved 2022): Blue Moon
https://science.nasa.gov/science-news/science-at-nasa/2004/07jul_bluemoon/
Quote: “Blue moons [caused by Krakatoa’s ash] persisted for years after the eruption. People also saw lavender suns and, for the first time, noctilucent clouds. The ash caused "such vivid red sunsets that fire engines were called out in New York, Poughkeepsie, and New Haven to quench the apparent conflagration," according to volcanologist Scott Rowland at the University of Hawaii.”
– At VEI 7, we get Super-Colossal eruptions, millennium-defining events that human civilization has only encountered a handful of times. Mount Tambora was a 4300m tall mountain until it exploded in 1815 and released 400 times more energy than the Tsar Bomba. 140 billion tons of ash and dust were shot halfway to space before smothering the world’s skies, turning them a sickly yellow. There was no summer the following year, crops died and over a hundred thousand people perished.
#NASA (2009): The year without a summer. Peering through volcanic veils
https://climate.nasa.gov/ask-nasa-climate/183/the-year-without-a-summer/
Quote: “In 1815, Mt. Tambora in Indonesia underwent the most deadly volcanic eruption in recorded history. The “super colossal” eruption, which measured 7 on the Volcanic Explosivity Index (VEI), pumped out enormous amounts of dust and ash, destroyed crops and vegetation, killed tens of thousands of people and even caused tsunamis. [...] But Tambora probably did cause the Year Without a Summer.”
Here is a comparison of the 1815 Mount Tambora eruption compared to other volcanic events in the past 2000 years:
#Oppenheimer, C. (2003): Climatic, environmental and human consequences of the largest known historic eruption: Tambora volcano (Indonesia) 1815. Progress in Physical Geography: Earth and Environment, Vol 27 (2)
https://journals.sagepub.com/doi/abs/10.1191/0309133303pp379ra
Quote: “Tambora continued rumbling intermittently at least up to August 1819. The paroxysmal phase of the eruption rapidly drained the magma reservoir and was accompanied by collapse of the volcano, toppling a formerly 4000 m (perhaps more than 4300 m according to Stothers, 1984) high summit and creating a 6 km wide, 1 km deep caldera. Today, Tambora’s crater rim reaches only 2850 m above sea-level, easily surpassed by Rinjani volcano on the neighbouring island of Lombok. ”
1.4 x 1014 kg corresponds to 140 billion tons.
The energy released is even more impressive. As shown in the chart below, the Tambora eruption was equivalent to 20,000 megatons of energy, which is equivalent to 83.7 exajoules.
#French, B. M. (1998): Traces of Catastrophe. A Handbook of Shock-Metamorphic Effects in Terrestrial Meteorite Impact Structures. LPI Contribution No. 954, Lunar and Planetary Institute, Houston, p. 15
https://www.lpi.usra.edu/publications/books/CB-954/CB-954.pdf
The Tsar Bomba is the largest nuclear device ever tested, with a yield of 50 megatons. It would take 400 of these to match the energy released by the Mount Tambora eruption.
#Encyclopaedia Britannica (2022): Tsar Bomba
https://www.britannica.com/topic/Tsar-Bomba
Quote: “Meant to be a show of Soviet strength, the three-stage bomb was unparalleled in power. It had a 100-megaton capacity, though the resulting fallout from such a blast was considered too dangerous for a test situation. Thus, it was modified to yield 50 megatons, which was estimated to be about 3,800 times the strength of the U.S. bomb dropped on Hiroshima during World War II.”
– This is the dreadful potential of volcanic eruptions, with famines across the other side of the world and even centuries-long cold periods being attributed to them.
#Miller, G. H. et al. (2012): Abrupt onset of the Little Ice Age triggered by volcanism and sustained by sea-ice/ocean feedbacks. Geophysical Research Letters, Vol. 39 (2)
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011GL050168
Quote: “Here we present precisely dated records of ice-cap growth from Arctic Canada and Iceland showing that LIA summer cold and ice growth began abruptly between 1275 and 1300 AD, followed by a substantial intensification 1430–1455 AD. Intervals of sudden ice growth coincide with two of the most volcanically perturbed half centuries of the past millennium.”
#McConnell, J. R. et al. (2020): Extreme climate after massive eruption of Alaska’s Okmok volcano in 43 BCE and effects on the late Roman Republic and Ptolemaic Kingdom. PNAS, Vol. 177 (27)
https://www.pnas.org/doi/full/10.1073/pnas.2002722117
Quote: “Volcanic fallout in well-dated Arctic ice core records, climate proxies, and Earth system modeling show that this transition occurred during an extreme cold period resulting from a massive eruption of Alaska’s Okmok volcano early in 43 BCE. Written sources describe unusual climate, crop failures, famine, disease, and unrest in the Mediterranean immediately following the eruption—suggesting significant vulnerability to hydroclimatic shocks in otherwise sophisticated and powerful ancient states. Such shocks must be seen as having played a role in the historical developments for which the period is famed.”
– The term “Super volcano” is a media invention and not a scientific term. The main issue with them is that not every eruption from a super volcano is a super eruption.
What makes super volcanoes special is that they have been waiting to erupt for hundreds of thousands of years. Pressure builds up in colossal magma reservoirs several kilometers deep, until it becomes strong enough to lift the rock above it by several meters. Rocks crack under the pressure, until they finally give way and huge amounts of billions of tons of gas and ash blast out at supersonic speed. An insane explosion of at least a thousand cubic kilometers that influences every corner of the globe. And yet, that is only a small portion of the magma reservoir.
#USGS (retrieved 2022): Questions About Supervolcanoes
https://www.usgs.gov/volcanoes/yellowstone/questions-about-supervolcanoes
Quote: “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).”
Ground uplift indicates that a reservoir is filling with fresh magma. Periods of unrest in smaller volcanoes already have the ground rising by several meters; larger reservoirs underneath potential supervolcanoes presumably raise the ground by even more.
#Rosi, M. et al. (2022): Defining the Pre-Eruptive States of Active Volcanoes for Improving Eruption Forecasting. Frontiers in Earth Science, Vol. 10
https://www.frontiersin.org/articles/10.3389/feart.2022.795700/full
Quote: “A state of major unrest was reached during the 1982–1984 crisis, when an uplift of ∼1.8 m was accompanied by high seismicity, increase in degassing (Del Gaudio et al., 2010) and surface fracturing (Orsi et al., 1999) at Solfatara.”
#Kilburn, C. R. J. et al. (2017): Progressive approach to eruption at Campi Flegrei caldera in southern Italy. Nature Communications, Vol. 8 (15312)
https://www.nature.com/articles/ncomms15312
Quote: “Unrest at large calderas rarely ends in eruption, encouraging vulnerable communities to perceive emergency warnings of volcanic activity as false alarms. A classic example is the Campi Flegrei caldera in southern Italy, where three episodes of major uplift since 1950 have raised its central district by about 3 m without an eruption.”
The mass of ash and materials expelled in this kind of eruptions lies comfortably in the range of several billions of tonnes:
#Costa, A. et al. (2018): Understanding the plume dynamics of explosive super-eruptions, Nature Communications. Vol. 9 (654)
https://www.nature.com/articles/s41467-018-02901-0
Quote: “Estimates of mass flow rates (MFRs) during these super-eruptions, obtained from different independent approaches, suggest that they are extremely high, ranging from 109 to 1011 kg/s”
Taking into account a conservative estimate of 12 hours of continuous blast (the lower limit for VEI 8 eruptions), this gives a total mass of ejecta of the order of 400·109 tonnes, i.e. many billions of tonnes.
And the speed of the flow is indeed expected to be supersonic:
#Bindeman, I. N. (2006): The Secrets of Supervolcanoes. Scientific American
https://www.scientificamerican.com/article/the-secrets-of-supervolca/
Quote: “Since that discovery, investigators have had to modify their reconstructions of supervolcano eruptions. Here is what they now generally expect from an event the scale of those that struck Long Valley and Yellowstone: Instead of a slow leak of red-hot lava as is seen creeping down the sides of Kilauea Volcano in Hawaii, these eruptions feature supersonic blasts of superheated, foamlike gas and ash that rise buoyantly all the way into the earth's stratosphere, 50 kilometers high.”
Shock waves (a wave front propagating faster than the speed of sound) have been used to model volcanic eruptions:
#Medici, E. F. et al. (2013): Modeling shock waves generated by explosive volcanic eruptions. Geophysical Research Letters, Vol. 41 (2)
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2013GL058340
Quote: “One characteristic of explosive volcanoes is the formation of atmospheric shock waves. [...] A shock wave differs from a sound wave in that it is traveling faster than the speed of sound. As the shock wave propagates, it gradually loses speed until the velocity is equal to the speed of sound, at which point it becomes a sound wave. In explosive volcanism (vulcanian to plinian), generation of an atmospheric shock wave is expected.”
– Super eruptions are like a boiling pot of water popping its lid off and spilling a bit off the top. Afterwards the ground collapses into the void left behind, forming a hole called a caldera. Under this caldera, pressure starts building again until the volcano gathers enough energy for another supereruption – but this could take hundreds of thousands of years.
The process leading to a supereruption is explained for example here:
#Bindeman, I. N. (2006): The Secrets of Supervolcanoes. Scientific American
https://www.scientificamerican.com/article/the-secrets-of-supervolca/
Quote: “A supereruption occurs after the pressurized magma raises overlying crust enough to create vertical fractures that extend to the planet’s surface. Magma surges upward along these new cracks one by one, eventually forming a ring of erupting vents. When the vents merge with one another, the massive cylinder of land inside the ring has nothing to support it. This “roof” of solid rock plunges down - either as a single piston or as piecemeal blocks - into the remaining magma below. Like the roof of a house falling down when the walls give way, this collapse forces additional lava and gas out violently around the edges of the ring”
#Miller, C. F. & Wark, D. A. (2008): Supervolcanoes and their explosive supereruptions. Elements, Vol. 4 (1)
https://www.researchgate.net/publication/240779372_Supervolcanoes_and_their_explosive_supereruptions
Quote: “As supervolcanoes rapidly emit material during eruption, whatever surface
structure existed before the eruption collapses into the evacuating chamber to form the characteristic caldera. The caldera size correlates with eruption size (Smith 1979), and
supervolcano calderas are appropriately gigantic: some are nearly 100 km across.”
The time between supereruptions can vary, but it’s always very long. For example, the last catastrophic eruption at Yellowstone took place more than 600,000 years ago, and still no supereruption is expected in the near future:
#USGS (retrieved 2022): Questions About Supervolcanoes.
https://www.usgs.gov/volcanoes/yellowstone/questions-about-supervolcanoes
Quote: “Over the past 640,000 years since the last giant eruption at Yellowstone, approximately 80 relatively nonexplosive eruptions have occurred and produced primarily lava flows. This would be the most likely kind of future eruption. If such an event were to occur today, there would be much disruption of activities in Yellowstone National Park, but in all likelihood few lives would be threatened. The most recent volcanic eruption at Yellowstone, a lava flow on the Pitchstone Plateau, occurred 70,000 years ago.”
– It is estimated, one of the few volcanoes capable of supereruptions on Earth could cause a catastrophic eruption every 17,000 years on average. That would make them far more frequent than comparable asteroid impacts.
However much we should be worried about asteroids, we should be ten times more worried about large, comparable volcanic eruptions.
#Mason, B.G. et al. (2004): The size and frequency of the largest explosive eruptions on Earth. Bulletin of Volcanology, Vol. 66 (8)
Quote: “Comparison of the energy release by volcanic eruptions with that due to asteroid impacts suggests that on timescales of <100,000 years, explosive volcanic eruptions are considerably more frequent than impacts of similar energy yield. This has important implications for understanding the risk of extreme events”
#Rougier, J. (2017): The global magnitude-frequency relationship for large explosive volcanic eruptions. Earth and Planetary Science Letters, Vol. 482
Quote: “Our estimate for the return period of 'super-eruptions’ (1000Gt, or M8) is 17ka (95% CI: 5.2ka, 48ka), which is substantially shorter than previous estimates, indicating that volcanoes pose a larger risk to human civilisation than previously thought.”
#Miller, C. F. & Wark, D. A. (2008): Supervolcanoes and their explosive supereruptions. Elements, Vol. 4 (1)
https://www.researchgate.net/publication/240779372_Supervolcanoes_and_their_explosive_supereruptions
Quote: “Given the current estimates of frequency of supereruptions (on the order of 10 per million years), it is nonetheless reasonable to infer that there have been many thousands—probably tens of thousands—over the course of Earth history. ”
-The most recent super-eruption is the Oruanui eruption 26,500 years ago in New Zealand. With the force of dozens of billions of tons of TNT, a Mount Everest- sized pile of explosives, a huge portion of the landscape was scooped out and thrown into the atmosphere. It left behind a caldera spanning 20km and it caused the entire Southern Hemisphere to undergo a period of abrupt cooling. Though among super-eruptions, it is a mere firework.
#Wilson, C. J. N. et al. (2006): The 26·5 ka Oruanui Eruption, Taupo Volcano, New Zealand: Development, Characteristics and Evacuation of a Large Rhyolitic Magma Body. Journal of Petrology, Vol. 47 (1)
https://academic.oup.com/petrology/article/47/1/35/1474189
Quote: “Here, we document the petrology of the youngest large TVZ caldera-forming event—the 26·5 ka, ∼530 km3 (magma) Oruanui eruption [...]
The Oruanui eruption (Wilson, 2001) generated 430 km3 of fall, 320 km3 of pyroclastic density current (PDC) and 420 km3 of primary intracaldera deposits, equivalent to ∼530 km3 of magma (of which 300 km3 is represented by sampleable extra-caldera deposits). The eruption is divided into 10 phases, was spasmodic and in total may have lasted for several months.”
This paper tries to assess the environmental impact of the devastating Oruanui eruption. The local forests were likely smothered in ash and destroyed to such an extent that it took thousands of years for them to recover.
#Holdaway, R. N. (2021): Palaeobiological evidence for Southern Hemisphere Younger
2 Dryas and volcanogenic cold periods. Climate of the Past Discussions
https://cp.copernicus.org/preprints/cp-2021-154/cp-2021-154.pdf
Quote: “Its roles as barrier or conduit probably changed with extrinsic events. For example, the Oruanui eruption of Taupo Volcano 25.6 ka BP (Vandergoes et al., 2013) would have deposited thick ash on the bridge (Vandergoes et al., 2013), destroying the vegetation (Oppenheimer, 2011), and making it uninhabitable by moa or anything else. Under the cold, dry glacial climate revegetation would have taken millennia.”
We can use a bit of math to calculate the energy released during such an eruption. The method is described here:
#de la Cruz-Reyna, S. (1991): Poisson-distributed patterns of explosive eruptive activity. Bulletin of Volcanology, Vol. 54 (1)
Quote: “A least squares regression has been calculated for these values (Table 6 and Fig. 9), and the relation:
log E = 0.78 Mv + 21.02
where E is the eruption energy expressed in ergs, and Mv the VEI value, has been found to fit the data with a correlation coefficient 0.70.”
We can translate that into an easy-to-use equation:
eruption energy (in ergs) = 10(0.78 x VEI + 21.02)
For the Oruanui eruption (VEI 8), this gives a value of about 1027.26 ergs, or 1020.26 Joules, which translates into more than 40 billion tonnes of TNT.
At a density of about 1600 kg/m3, 40 billion tonnes of TNT would take up a volume of about 25·109 m3, or 25 km3. Piled in an area of 3 km2, that amount of TNT would be almost as tall as Mount Everest.
– The Lake Toba eruption of 74,000 years ago was a much more significant turning point in history. It released a gargantuan 5300 cubic kilometer volume, enough to blanket parts of South Asia in 15 cm of ash and trigger a rapid 4°C drop in global temperatures. It’s possible that the volcanic winter lasted ten years, followed by worldwide droughts for centuries. Earth’s climate might have not recovered for a thousand years, but scientists are still researching to learn more about this spectacular event.
#Osipov, S. et al. (2021): The Toba supervolcano eruption caused severe tropical stratospheric ozone depletion. Communications Earth & Environment, Vol. 2 (71)
https://www.nature.com/articles/s43247-021-00141-7
Quote: “The Toba supervolcano eruption at 74 ka has been the largest natural disaster known in the past 2.5 million years8. It injected up to 100 times more SO2 into the stratosphere than Mt Pinatubo, and climate model simulations suggest a global cooling of 3.5–9 °C, and up to 25% reduction in precipitation”
We call these drastic global coolings caused by volcanic eruptions ‘volcanic winters’.
#Encyclopaedia Britannica (2018): Volcanic winter
https://www.britannica.com/science/volcanic-winter
Quote: “volcanic winter, cooling at Earth’s surface resulting from the deposition of massive amounts of volcanic ash and sulfur aerosols in the stratosphere. Sulfur aerosols reflect incoming solar radiation and absorb terrestrial radiation. Together these processes cool the troposphere below. If sulfur aerosol loading is significant enough, it can result in climate changes at the global scale for years after the event, causing crop failures, cooler temperatures, and atypical weather conditions across the planet.”
The impact of the Toba super-eruption was so huge because of the quantity of material it ejected, accompanied by an impressive sulfur load.
#Osipov, S. et al. (2021): The magnitude and impact of the Youngest Toba Tuff super-eruption. Frontiers in Earth Science, Vol. 2
https://www.frontiersin.org/articles/10.3389/feart.2014.00016/full
Quote: “These new fallout volume estimations indicate that the total volume of the material erupted (including the massive pyroclastic density current (PDC), 1500 km3 DRE, deposits on Sumatra) was ~5300 km3 DRE.[...]
The largest historic eruption, the 1815 Tambora event, and the AD 1783–1784 Laki (Skaftár Fires) eruption both released comparatively minute amounts of SO2, ~55 Tg (Self et al., 2004) and 122 Tg (Thordarson et al., 1996; Thordarson and Self, 2003) respectively. These sulfur loads resulted in mean surface cooling of −1.0 to −1.5°C that lasted a few years (Thordarson and Self, 2003). The YTT sulfur load was an order of magnitude greater but it is not clear that the change to the radiative forcing would have been as large. ”
The amount of ash deposits has also been documented:
#Lundberg, J. & McFarlane, D. A. (2012): A significant middle Pleistocene tephra deposit preserved in the caves of Mulu, Borneo. Quaternary Research, Vol. 77 (3)
Quote: “On the southern Indian subcontinent, the Toba ash averages 15 cm thick, with local deposits exceeding 6 m (Westgate et al., 1998; Petraglia et al., 2007), while parts of Malaysia were buried as deeply as 9 m”
The actual impact and reach of the Toba volcanic winter have been debated, but some researchers have related it to the beginning of a 1000 year “stadial” (of cooler climate) period
#Zielinski, G. A. et al. (1996): Potential atmospheric impact of the Toba Mega-Eruption ∼71,000 years ago. Earth Science Faculty Scholarship 192
https://digitalcommons.library.umaine.edu/cgi/viewcontent.cgi?article=1192&context=ers_facpub
Quote: “An ∼6-year long period of volcanic sulfate recorded in the GISP2 ice core about 71,100 ± 5000 years ago may provide detailed information on the atmospheric and climatic impact of the Toba mega-eruption. Deposition of these aerosols occur at the beginning of an ∼1000-year long stadial event, but not immediately before the longer glacial period beginning ∼67,500 years ago. Total stratospheric loading estimates over this ∼6-year period range from 2200 to 4400 Mt of H2SO4 aerosols. The range in values is given to compensate for uncertainties in aerosol transport. Magnitude and longevity of the atmospheric loading may have led directly to enhanced cooling during the initial two centuries of this ∼1000-year cooling event.”
– The largest volcanic events we know of were not really huge explosions, but floods of millions of cubic kilometers of lava. The grand finale were the Siberian Traps around 250 million years ago, a continuous release of lava for two million years. They raised the ocean temperatures to over 40°C, which caused the Permian–Triassic extinction, killing over 90% of all species. Earth’s surface needed 9 million years to recover. These sorts of eruptions don’t change the climate: they are the climate. But thankfully, we haven’t seen anything even remotely close to that scale in many millions of years.
#Ivanov, A. V. et al. (2013): Siberian Traps large igneous province: Evidence for two flood basalt pulses around the Permo-Triassic boundary and in the Middle Triassic, and contemporaneous granitic magmatism. Earth-Science Reviews, Vol. 122
https://www.sciencedirect.com/science/article/abs/pii/S0012825213000652
Quote: “The Siberian Traps large igneous province is of enormous size (~ 7 × 106 km2) and volume (~ 4 × 106 km3).”
Analysis of geological records puts these eruptions as directly coinciding with the worst extinction in the planet’s history, and very likely having caused massive climate change due to the addition of enormous amounts of greenhouse gases into the atmosphere.
#Burgess, S. D. & Bowring, S. A. (2015): High-precision geochronology confirms voluminous magmatism before, during, and after Earth’s most severe extinction. Science Advances, Vol. 1 (7)
https://www.science.org/doi/10.1126/sciadv.1500470
Quote: “The end-Permian mass extinction was the most severe in the Phanerozoic, extinguishing more than 90% of marine and 75% of terrestrial species in a maximum of 61 ± 48 ky. Because of broad temporal coincidence between the biotic crisis and one of the most voluminous continental volcanic eruptions since the origin of animals, the Siberian Traps large igneous province (LIP), a causal connection has long been suggested. Magmatism is hypothesized to have caused rapid injection of massive amounts of greenhouse gases into the atmosphere, driving climate change and subsequent destabilization of the biosphere.”
It has been argued that the temperatures reached lethal levels:
#Sun, Y. et al. (2012): Lethally Hot Temperatures During the Early Triassic Greenhouse. Science, Vol. 338
Quote: “The late Smithian Thermal Maximum (LSTM) marks the hottest interval of entire Early Triassic, when upper water column temperatures approached 38°C with SSTs possibly exceeding 40°C”
And that the global effects might have lasted for millions of years:
#Chen, Z. Q. & Benton, M. J. (2012): The timing and pattern of biotic recovery following the end-Permian mass extinction. Nature Geoscience, Vol. 5
Quote: “The aftermath of the great end-Permian period mass extinction 252 Myr ago shows how life can recover from the loss of >90% species globally. The crisis was triggered by a number of physical environmental shocks (global warming, acid rain, ocean acidification and ocean anoxia), and some of these were repeated over the next 5–6 Myr. [...] a stable, complex ecosystem did not re-emerge until the beginning of the Middle Triassic, 8–9 Myr after the crisis.”
– So. Should you be scared of super-volcanoes? Definitely not. They’ve been used to frighten many people and are overhyped as an unavoidable apocalypse. The most famous one, Yellowstone, will erupt again, but it will be relatively small eruptions. Natural disasters for sure, but not enough to devastate the US or come close to ending humanity.
The chance of a VEI 8 eruption in the next few hundred years is less than 2% and more importantly, it would not come as a sudden surprise. However, less powerful but more frequent eruptions can also do serious damage to our civilizations and are in many ways a much greater concern.
Predicting future volcanic eruptions gives very different probabilities depending on the method you use.
#Mason, B.G. et al. (2004): The size and frequency of the largest explosive eruptions on Earth. Bulletin of Volcanology, Vol. 66 (8)
Quote: “The largest eruptions on Earth are, by their nature, rare events, whose size and frequency cannot be deduced from observations of smaller events. For example, extrapolating the power-law functions that describe the relationship between size and frequency of small to medium-sized events to assess the behaviour of rare large events is unreasonable, since this extrapolation suggests that one M8 eruption should occur about every 1,200 years (e.g.Decker 1990; Pyle 1995), yet the last known such event was at 26.5 ka. Two approaches may be used to derive estimates of the likely scale and occurrence rate of large events.”
Nonetheless, we can estimate a low but troublesome probability of a super-eruption in the next few hundred years. There is a significant chance that a super-eruption will occur in the next million years, but by then we might have advanced so much that it would not be a risk to us at all.
#Mason, B.G. et al. (2004): The size and frequency of the largest explosive eruptions on Earth. Bulletin of Volcanology, Vol. 66 (8)
Quote: “On the basis of the activity during the past 13.5 Ma, there is at least a 75% probability of a M8 eruption (>1015 kg) occurring within the next 1 Ma. There is a 1% chance of an eruption of this scale in the next 460–7,200 years.”
We should not ignore the possibility of one of the smaller but more frequent eruptions occurring in the near future, where will be vulnerable to its effects.
#Newhall, C. et al. (2018): Anticipating future Volcanic Explosivity Index (VEI) 7 eruptions and their chilling impacts. Geosphere, Vol. 14 (2)
Quote: “We noted here that the recurrence frequency of a VEI 7 eruption somewhere in the world is between 1 and 2 per thousand years, probably closer to 2 per thousand years. We also noted that pyroclastic flows from VEI 7 could erase an entire city or region, and ash fall and aerosols could have global impacts on air travel, supply chains, and climate. The worst death tolls in historical eruptions are in the tens of thousands (Tanguy et al., 1998; Witham, 2005; Auker et al., 2013), whereas a VEI 7 eruption near an urban area today potentially could kill millions.”
– So we must watch for slow changes in magma reservoirs, like ground swelling and temperature increases, to get an early warning that can save the lives of people living the closest to a volcano. And there’s time to develop solutions that can remove sulfur and ash from the stratosphere to eliminate the root cause of the climate disruption we’ve seen from previous eruptions. Who knows, maybe we’ll even be able to turn this force of destruction into an agent for good by exploiting the geothermal energy held in their giant magma reservoirs.
Predicting volcanic eruptions relies on scientists monitoring the volcano’s activity and comparing it to its normal behaviour.
#USGS (retrieved 2022): VHP uses monitoring data and volcanic history to forecast eruptions
https://www.usgs.gov/programs/VHP/vhp-uses-monitoring-data-and-volcanic-history-forecast-eruptions
Quote: “Key to success in short-term volcanic eruption forecasting is being able to recognize when a volcano is moving away from its background level of activity. To do so, volcanologists must collect volcano-monitoring data during times of quiescence. With reference to these background measurements, scientists are better able to interpret changes that are caused by magma movement or pressurization, including shifts in seismicity, appearance of ground deformation, and change in character or rate of gas emissions.”
In the future, volcanoes could become a useful resource.
#Cassidy, M. & Mani, L. (2021): On the assessment of volcanic eruptions as global catastrophic or existential risks. Effective Altruism Forum
Quote: “Some may well ask, apart from preparing for the hazards themselves, is there anything we can do to interfere with them to lessen their impact somehow? It’s topic that that has been received some attention from other disciplines (Dekenberger and Blair, 2018, Wilcox et al., 2015), but it has largely ignored by volcanologists, however we think that this may all change in the next few decades due to recent scientific developments which may drill into volcanoes to tap their fluids rich in ‘critical metals’ (e.g Copper and Lithium) that are needed for green technologies, as well as so called ‘supercritical’ geothermal energy. Some of this is a long way off yet, but there’s lots that may change in the long-term future of volcanoes, so watch this (volcanic) space.”
Scientists are also focusing on more resilient food production methods to deal with potential disasters and the pressures of climate change. This will help mitigate the impact of a volcanic eruption.
#Tzachor, A. et al. (2021): Future foods for risk-resilient diets. Nature Food, Vol. 2
– We’ve done this work for so many other disasters and we are already doing things we could only have dreamed about decades ago, like sending a probe to perform our first asteroid redirection test. With determination, humanity really can solve anything. So while deep below us an angry hell is churning and waiting for its moment, you can sleep well tonight.
#NASA (retrieved 2022): DART
https://www.nasa.gov/planetarydefense/dart
Quote: “DART is a spacecraft designed to impact an asteroid as a test of technology. DART’s target asteroid is NOT a threat to Earth. This asteroid system is a perfect testing ground to see if intentionally crashing a spacecraft into an asteroid is an effective way to change its course, should an Earth-threatening asteroid be discovered in the future.”