Currently, the tinfoil-hat brigade are working themselves up into a shitless frenzy over a run of seismic activity underneath Yellowstone Lake. People talking about the end of civilisation, ELEs, and even the occasional moron wittering on like a dribbling idiot about all the Planet X/Nibiru nonsense being to blame. Nibiru is coming!! Jeez, those morons will work that into any event. Idiots.
So what’s all the fuss then, eh? More after the jump.
Well, Yellowstone Park just happens to one of a small number of locations around the world where you can find a Supervolcano – the biggest and most powerful of all volcanoes. These things would make the Mount St. Helens eruption look like “a bit of an old man’s dribble”.
Now, Supervolcano is not actually a genuine scientific term. It was in fact coined by the BBC on their scientific magazine programme Horizon – but many geologists and vulcanologists will use the term in public as it has a generally understood meaning (and carries more impact), and may sometimes refer to them as Megacaldera. In fact, an eruption that rates 7 or 8 on the Volcanic Explosivity Index (VEI) would typically be referred to in the field as a Super Eruption – not nearly as exciting. Essentially, a Supervolcano is no different to your bog-standard volcano that we have all come to know and love (like Etna, Krakatoa, Mt. St. Helens and so on) apart from in one main respect – size. Anything that spits out over 1000 cubic kilometres of rock is classed as a Supervolcano. Mt. St. Helens spewed just 2 cubic kilometers of rock out. Feeb.
Most of Yellowstone Park sits in a volcanic caldera – a region of the earths’s crust that has dropped to form a sort of crater. The floor of the caldera is effectively the ‘cap’ that sits atop the massive magma chamber under the surface. In a regular volcano, the structure is the familiar pointy cone, with volcanic deposits…er…depositing…at the top and down the sides. With a Supervolcano, the explosive force is such that there is no cone building – as the magma or pulverized magma (depending on the type of eruption) vents, the crust drops down to fill the space left by the magma. In the case of Yellowstone, this caldera is huge – really huge. 34 miles by 45 miles, approximately, and the “cliff” formed by the drop can be in places up to 1,000 feet high. Quite a big chicken, then.
It is thought – as far as we can tell – that the human race has only ever been around for a single Supervolcano eruption. Lake Toba, in Sumatra. This lake, over 1,000km long and 30km wide, was the site of a massive super eruption around 75,000 years ago – as far as we know, the largest in the last 25 million years. With a VEI of 8, it is believed that the ash cloud from the eruption reached the very edge of space and was so large and so dense that it covered the skies over much of India and deposited up to 10cm of ash right across that landmass. It is believed that up to 1010 tonnes of sulfur dioxide were released into the atmosphere with two noticeable effects: firstly, the sulfur dioxide combined with water to create a rain of sulfuric acid. Secondly, it also attached to dust particles in the atmosphere to form droplets, making the upper atmosphere more reflective and, as a result, reduced the amount of heat and sunlight reaching the earth’s surface. It is believed the the average global temperature could have dropped anywhere between three and five degrees Celcius. The drop in temperature, combined with the more localised ashfall, would have meant that very little plant life would have survived in the Asian continent, and it is possible that globally there would have been a devastating reduction in plant and animal life due to the harsh, ‘volcanic winter’ that would have ensued (and lasted for many years). Studies of mitochondrial DNA in the world’s human population seem to suggest that at exactly this time the human race went through a ‘bottleneck’. Studies of DNA in the indigenous poulation of Inida has been shown to have the least mitochondrial variation of all the world’s populations, and is is postulated that the entire human population in India may have been as low as 600 – and across the globe, reduced to tens of thousands.
So…we come to the Yellowstone Caldera. With its massive magma chamber, Yellowstone has the potential to at least equal Toba in violence and scale. It is entirely possible that the Yellowstone volcano could erupt with an event easily at a VEI of 8. But it is not as clear cut as that.
It is believed, from gelogical evidence, that the volcano has erupted on this scale three times. 2.1 million years ago, 1.3 million years ago, and 640,000 years ago. There have also been numerous smaller eruptions more recently and throughout this time, the latest being a lava flow about 70,000 years ago, and much smaller in scale. Today, the only obvious volcanic activity is in plain sight every day – the hydrothermal vents dotted about the park (such as Old Faithful). Yellowstone contains almost two-thirds of the world’s hydrothermal vents. Of course, there is also the rise and fall of the base of the caldera, but that is not something the naked eye notices.
There are two possibilities, should the volcano decide that time is up and it is ready to blow. The volcano could erupt as a massive lava flow: the more traditional view of a volcano, with rivers of lava – super-hot molten rock – pouring out to the surface. Whilst these would cause tremendous local damage and incinerate anyting upon contact, this would offer the least threat to life in the area. After all, molten rock does not travel very fast. You could likely walk away from it.
However, the other option is the more devastating. If the explosion is poweful and fast enough – if the built-up pressure is great enough – then the magma could be pulverised by the force of the explosion. This pulverised matter – tiny particles of magma and basalt dust – would be blown skywards in a massive column of dust, ash, and pumice, driven higher by its immense heat. As Toba showed, this column – should the blast and heat be powerful enough – could reach the edge of space itself. Pretty nasty so far. But then, as the particles cool, they start to fall. Firstly, as the column collapses, the heaviest debris would collapse out sideways from the base of the column. This is called a pyroclastic flow, and this is the point at which things get very bad, very quick.
The clouds that billowed out from the side of Mount St. Helens, ripping through the trees and forests, were an example of a pyroclastic flow. Doesn’t sound too scary? Then bear in mind that the ash and dust in the flow is six times as dense as snow, can be up to several hundred degrees Celcius, and can travel at up to several hundred kilometres per hour. If you see one of these bearing down on you, you are already dead. It is postulated that, should Yellowstone erupt with a VEI of 8 in this way, everything within, say, a hundred miles of the caldera would be vaporized by the flow. And, even if the flow was not that hot – not enough to vaporize you on the spot, well, that would be worse. Ask the people who died in Pompeii. If they weren’t killed by ashfall, or by building collapse caused by the weight of the ash and pumice, they were caught in the flow, cooked, and fried. Studies of the remains at Pompeii show widespread damage to the skulls – where the brain simply overheated to such a degree that it exploded and cracked or shattered the skull from the inside. And that was just a feeble, run of the mill pointy volcano.
What about the lighter dust and ash? Well, this would eventually fall to earth in a more genteel manner. Ashfall is the biggest killer when it comes to volcanoes. The ash itself, as I explained, is made of tiny, microsopic particles of pulverised magma, basalt and minerals – basically rock. Small enough to breathe in. The particles are not like normal fire ash, rather they are jagged, pointy, nasty little things and full of tiny cavities and holes from the gas that was contained in the magma (the gas dissolved in the magma is what creates the enormous pressure that can lead to powerful explosive eruptions). This makes the ash very porous. The ashfall from a Supervolcano would be devastating, and over an unimaginable area. It is thought that, should the eruption have a VEI of 8, then the ashfall would reach as far as the East Coast of North America, and possibly reach down south as far as Florida, if not further. Depending on your distance from Yellowstone, the ashfall could range in depth from several centimtres to twenty or thirty metres. But we are not talking of an incovenience here when we talk of ashfall. The ash is all-pervading, gets into every nook and cranny, and is utterly, utterly fatal. Engines would not function. Aircraft flying through volcanic ash simply stop and fall. Hiding inside would not protect you – as ash is many times denser than snow most houses and buildings would suffer roof collapse due to the sheer weight. Power lines and overhead cables would collapse and snap. And worst of all? Remember, the ash is porous. If you were to breathe this in, your lifespan would not be very long; the ash would very quickly mix with the fluids in your lungs and mucous membranes to form a solid cement.
Conservative estimates currently suggest that if Yellowstone was to do it’s worst, the death toll in North America could be up to several million over the course of the first few weeks. And geologists say that as far as they know, a VEI 8 eruption could go on for days, weeks, or even months. There is no way to tell.
Most of North America’s arable farmland would be rendered useless, buried under the thick ash layer. Most of North America would be uninhabitable, and even if there could be some sort of sustained cleanup operation, this would likely take decades, if not a generation. Rescue efforts would be, let’s face it, impossible. With a huge percentage of the country’s population dead or dying in the first few weeks, who would rescue whom? With absolutely no infrastucture of any kind over most of the country, it would not be good times. Canada and Mexico would be faced with being next door to a humanitarian crisis the like of which humanity has never experienced.
And what of the global impact? In a word, devastating. Although outisde the U.S. there would be no ashfall, after only a few weeks the eruption would start to have its effect around the globe. With unimaginable amounts of dust still in the atmosphere all over the globe, and with hundreds of millions of tonnes of sulfur dioxide belched out of the caldera, acid rain – real acid rain – would soon follow. As the U.S. economy collapsed overnight – due to the fact it no longer existed – so too would the rest of the world markets. As the global temperatures plummeted over the following weeks and months, man’s ability to grow and sustain crops and livestock would all but vanish. There would be nowhere to go – it would be the same everywhere. Life would die out around the world. We would have no way to feed ourselves. There would be no viable economy. Most of society’s rigid infrastructure would collapse. After all, would you go to work as normal whilst ice sheets formed around you, or whilst you starved to death? Much of the Northern Hemisphere would be cloaked in a deep layer of ice in a new and sudden ice age. Mass pogroms and migrations to the Equatorial regions and Southern Hemisphere would take place. Given our violent and territorial nature, and ever-dwindling resources, this would soon lead no doubt to conflict. We really are that stupid. And even these migrations would cull the population further. After all, you would be on foot – who would be driving a train or a bus, or flying a plane at the end of civilisation? Early man survived catastrophes in the past because of his way of life – it was migrant, and flexbile, he lived off the land. The interdependece we now have with technology, communication and transport – our inability to survive off the land without assistance – means that we are weak, and this weakness would be our downfall.
Current convervative estimates as a worst-case scenario suggest that the estimated death toll from the volcano, starvation, cold, exhaustion, disease and conflict would be in the billions. There would be no safe haven , no ‘higher ground’ to evacuate to. No spared land where crops can grow and animals can be raised.
So, you can see why the tin-foil hat brigade are a bit twitchy right now. The quakes under Yellowstone Lake are frequent – at the last time I checked, about 60 in the last three days, ranging from 1.8 to 3.5 in magnitude. But on the flipside, the U. S. Geological survey advise that such collections of quakes – called ‘swarms’ – are commonplace all over Yellowstone. They may just be a sign that magma is moving around under the surface, and the crust is jostling about as it does so, hopefully releasing pressure as it goes. They advise that if anything it could just be that all that happens is that a few cracks appear and hydrothermal venting takes place. Or nothing could happen. There have been massive earthquakes causing slippage and landslides in the park over the last 50 years, and nothing happened as a result. The quakes could be a result of the crust shifting, or fault lines moving. They advised that the common figure of the last eruption being 640,000 years ago is actually slightly off, and that rather than an eruption being ‘overdue’ (the popular thinking being that it erupts every 600,000 years or so) the actual last eruption was more like 750,000 years ago. And that volcanoes don’t follow a timetable. They don’t erupt on the clock. It could be another 50,000 years before it erupts again.
On the other hand, they advise, they just don’t know. Nature does what it likes, and man is not in control. It could erupt tomorrow. No way to tell. They don’t even have a way to know for sure how much magma is down there, or what exactly it is doing. The only thing they do know for certain is that Yellowstone will erupt, someday.
Although there have never been such swarms recorded under the lake before.
My thinking: don’t sweat it. Most likely nothing will happen, and this is just normal seismic activity. And if it isn’t?
You would do what, exactly?