Location:
North-West Wyoming, USA Yellowstone is one of the largest volcanos in the world, some say the largest. The magma chamber lies only a few km below the surface. Yellowstone is known as a restless caldera because it pulsates e.g. expands and contracts.
In the National park there are around 3000 Earthquakes a year due to the techtonic activity of the area. Mt St Helens was the most violent eruption in american history - killing 57 people and ejecting 1km3 of volcanic material. Krakatoa was 17x bigger and killed 36,000 people. Yellowstone is 2,500x larger then Mt St Helens. In the last 2 million years Yellowstone has produce 3 eruptions. The Caldera is 85km by 45km, large enough to hold a city with a population of 18 million. The magma chamber is 75km long, 45km wide and 8km deep. This can be measured by sending seismic waves through the chamber, because the waves travel slower through the magma then through solid rock. The eruption, if it happened, would be equivilant to 1000 Hiroshima bombs. The main damages of the eruption would come from the Pyroclastic flows from the vents of the volcano, They travel up to 700km/h and reach up to 800 degrees celcius, so anything within a 100 mile radius would be obliterated. It would be more than an incovenience if it went off, the whole world would be affected.
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History of Yellowstone
The first super eruption at Yellowstone was 2.1 million years ago and projected 2-3000km3 of rock, ash and gas. The next was 1.3 million years ago and the eruption formed a Caldera with the area 18 by 23 miles. The most recent eruption was 640,000 years ago, this formed the current Yellowstone caldera that we see today. o on average that's one every 600,000 years, which means we are 40,000 years overdue. However with these sorts of timescales that could mean it could go up next year or 1000 years from now.
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