Anatomy of a Supervolcano
by Alex Lee, age 13
Most people know about ordinary volcanoes, but many have not heard about unique supervolcanoes. These extremely rare volcanoes are the worlds most powerful. They are rated number eight—the highest figure on the Volcanic Explosivity Index.
Earlier this year, the Icelandic volcano, Eyjafjallajökull, caused a delay in air travel over Europe and the Atlantic for six weeks, due to the dense ash it created in the air. It released about 0.03 cubic miles of boiling material. A supervolcano, however, on average, releases about 240 cubic miles of dusty ash and hot magma fragments per eruption.
“Supervolcano eruptions occur on average once every 100,000 years,” says Jacob Lowenstern, a senior geologist at the Yellowstone Volcano Observatory and the United States Geological Survey.
Supervolcanoes form when a giant pool of burning magma accumulates below the Earth’s surface. Magma and lava are two different things. Magma is the term for the molten material that sits beneath the Earth’s surface, while the material that forms after an eruption is called lava.
When a supervolcano erupts, the earth around it falls into the hole created by the volcano and forms a depression called a caldera. In regular volcanoes, the magma rises slowly in small increments forming a conical vent. If the volcano is well shaped, it becomes conical.
Twenty-seven million years ago, Colorado had an extreme eruption of a supervolcano. It is estimated that 1,200 cubic miles of volcanic material was blown into the atmosphere.
That explosion isn’t the only time western North America has erupted with volcanic activity. Three of the largest supervolcanoes known to scientists occurred in the region that is now Yellowstone National Park. These eruptions have been dated as far back as a million years. The more recent eruption of a supervolcano was 640,000 years ago.
Our planet hasn’t stopped producing massive volcanic forces. In fact, scientists predict another will occur within several thousand years. Such an event would spew molten material over a large portion of the Western United States. If this were to happen it could heavily alter the way our Earth works. For example, it would disrupt the Earth’s climate and dramatically affect agricultural seasons.
[Source: Science Illustrated]