Yellowstone National Park is known for its iconic geysers and landscape. The park boasts the largest collection of hydrothermal features on Earth. However, this phenomenon is caused by a five-mile-deep caldera, or reservoir, filled with hot magma that lurks beneath the park. The geothermal activity in Yellowstone is so immense that it is classified as a supervolcano. Supervolcanoes are similar to regular volcanoes except they are approximately a thousand times more powerful. Fortunately, the Yellowstone supervolcano is among the most monitored volcanoes on the planet, and there is no indication of an eruption any time soon. Even so, it remains an endless source of apocalyptic fascination for multiple news agencies, and it’s not hard to see why. If it were to erupt today, the results would be disastrous.

Past Eruptions

Yellowstone Calderas

National Park Service
via Wikimedia

Throughout history, Yellowstone has had three massive eruptions: 2.1 million years ago, 1.3 million years ago, and 664,000 years ago. The volcano’s last super-eruption occurred at Yellowstone Lava Creek, and it is thought to be the largest known blast on earth. It filled approximately 240 cubic miles of the atmosphere with ash and pulverized rock. Furthermore, it covered half of the country in dangerous ash. It ejected so much material that it left a 34-mile-by-50-mile depression, which is approximately the size of Rhode Island. This depression is what we know as the Yellowstone Caldera. However, it is highly unlikely that the supervolcano will erupt at this magnitude again.

Small eruptions, although extremely rare, also occurred throughout history. The majority of documented eruptions in Yellowstone are small lava flows, and the last occurrence was at Pitchstone Plateau an estimated 70,000 years ago.

What Would an Eruption Look Like Today?

The Yellowstone Caldera is among the most seismically active areas on earth, and there are regular earthquakes detected in and about the supervolcano. With the all the geothermal activity, it is no surprise that news agencies are constantly reporting on the potentially catastrophic “super-eruptions.” A super-eruption is any eruption that measured a magnitude of eight or higher on the Volcano Explosivity Index. Furthermore, it must eject at least 1,000 cubic kilometers of material.

Due to the threat the Yellowstone supervolcano poses, scientists have heavily monitored and studied it. They found that, if the supervolcano erupted again at the magnitude of the past eruptions, it would cover Wyoming, Montana, Idaho, and Colorado in three feet of volcanic ash. Additionally, it would cover the Midwest in a blanket of ash. This amount of ash can kill plants and animals. Furthermore, it would damage human civilizations by crushing roofs, damaging buildings, shutting down power plants, and smothering crops.

However, it is highly unlikely that the supervolcano will have a large eruption. However, if it were to erupt, the underground activity would provide warnings decades before the eruption occurs. Small eruptions and earthquakes occur at a high frequency and are often ignored. Nevertheless, small eruptions are still very rare occurrences.

Is Yellowstone The Only Supervolcano?

While Yellowstone is the most well-known supervolcano, it is not the only one on Earth. Super-eruptions are fairly rare, so it is estimated that we experience one every 100,000 years. Furthermore, geologists found evidence of at least 47 other super-eruptions throughout history, and the most recent occurred in Lake Taupo in New Zealand around 26,000 years ago. The largest eruption came from the gargantuan Toba Eruption around 74,000 years ago. The effects were so catastrophic that it caused a 6-10 year global cooling period that is projected to have almost caused the nascent human race to go extinct.


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