On our planet, there are volcanos, and supervolcanoes. The latter do not have a definition that everyone accepts, but what everyone agrees on, is that they cause catastrophes at a global level. Many scientists use this term to refer to eruptions of exceptional violence and magnitude. On Earth, there are about 20 supervolcanoes. One of them is situated under the Yellowstone national park. We call it the Yellowstone supervolcano.
From what we know, the eruptions of this enormous volcano are regular. In the last 2.1 million years, it has made eruption 3 times, with an interval between them of approximately 700,000 years. The last explosion of the Yellowstone supervolcano took place 640 000 ago, so we can expect another of its colossal explosions during the next 100,000 years.
What will happen before its next explosion?
Shortly before the explosion, the land around the national park would be elevated a little bit, and the geysers and the hot springs would heat themselves rapidly until surpassing the boiling point of water. Moreover, it is possible that they turned extremely acid.
Before the big explosion a series of ever-stronger earthquakes, heading towards the centre of the volcanic caldera, would also be produced, which would indicate that the magma would be rising quickly through the Earth’s crust. Then, the rock that puts a top to the supervolcano’s caldera would break, letting the lava, ash, rocks and other materials go out into the atmosphere, where they would cause a catastrophe on a global scale.
After the eruption
However, the series of events that will take place before the eruption, won’t be anything compared to the disasters that will be produced once the volcano exploded. According to some estimations, people situated at tens or hundreds of kilometres around the volcano would be in danger. After breaking the rock that makes of “roof” to the volcanic caldera, a column of ash, lava, gases and rocks would rise in the air, that would reach a height of 25 kilometres. This column would be maintained during some days, and the ash and gases would spread through the atmosphere. The ash, which would be toxic and would harm the lungs in case of being breathed, would bury under a 90-centimetre layer thousands of square kilometres around the Yellowstone supervolcano. This would plunge the region into darkness. The crops would be lost, as the ash spread out, it could reach the country’s coasts, where the most people live in.
This would only be in the United States. At a global level, the ash and other components released by the eruption would cover the atmosphere, preventing any sunlight to reach the Earth’s surface. Consequently, the temperatures of the planet would descend abruptly, and in the absence of light and the sudden temperature change, would make many plants to die. The ash fallen from the atmosphere would make the water not to be potable. Without water and food (due to what agriculture would suffer), and adding to it the effects of the ash, deaths would be counted in millions.
The end of humanity?
Nowadays we haven’t got sufficient knowledge to know which duration will have, which will be the real consequences, and what will the global impact be, of these enormous eruptions. Nevertheless, we know that, whatever may happen, the supervolcano that hides under the Yellowstone national park won’t provoke the extinction of our civilization, nor of any other form of life on the Earth. In fact, the human species already went through the explosion, 75,000 years ago, of the Toba supervolcano. The explosion of this volcano was much greater than the ones of Yellowstone, with a disastrous environmental impact. It is thought that the Toba eruption was about to cause the extinction of our species, leaving alive only 2,000 persons. We see this reflected in our DNA: there can be more genetic variation between two chimpanzees than between most part of all human beings. Even if that eruption was about to leave extinct our species, the latter one survived, despite not having access to the technology that we have in our days.