Tourists flock to Yellowstone National Park each year to view the geysers that bubble and erupt throughout it. What most of these tourists do not know is that these geysers are formed by a caldera—a hot crater in the earth’s crust—which was created by a series of three eruptions of an ancient super volcano. These eruptions, which began 2.1 million years ago, spewed between 1,000 to 2,450 cubic kilometers of volcanic matter at such a rate that the volcano’s magma chamber collapsed, creating the craters.
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