The Yellowstone Caldera, a.k.a the Yellowstone Supervolcano, is the volcanic caldera located in Yellowstone National Park in the northwest corner of Wyoming, in which the vast majority of the park is contained. The major features of the caldera measure about 34 by 45 miles (55 by 72 km). Based on best geological evidence, the supervolcano erupted 2.1 million, 1.3 million, and 640,000 years ago. Given its size and location, an eruption of the volcano would have a disastrous impact across the Earth, not just in the United States.
Yellowstone Supervolcano in Supervolcano
In the second decade of the 21st century, the Yellowstone Supervolcano erupted, causing a national disaster in the United States and around the world.
Approximately two years before the Supervolcano erupted, a series of 5.0 to 5.5 magnitude earthquakes began at Sour Creek and Coffee Pot Springs. While the former had had a magma dome under it for some time, it was found that the latter had a newly formed dome. The shifting magma was the source of the quakes.
By a year and a half before eruption, a number of geologists had expressed concerns of a major eruption to the US Department of the Interior. The magma dome under Coffee Pot Springs had been growing at a rate a dozen times faster than any previously recorded causing significant bulging. This had disrupted the geyser displays (especially Old Faithful) causing upset among tourists. Also, the earthquakes had continued. Scientists, having never observed a Supervolcano eruption, were divided whether this signaled a eruption or not.
Yellowstone continued to be studied by a team of geologists led by Larry Skrtel of the US Geological Survey. About a year before eruption, this team discovered that Coffee Pot Springs had "gone nuts": a brand new geyser threw water a hundred feet into the air and springs were no longer just pools but blorping boiling water 8-10 feet high along with new, agitated springs forming.
About six months before eruption, a conventional volcano began forming and erupting at Ranger Lake, on the other side of the park. While there had been eruptions at the park in the past (although not recently) the distance between the two events caused increased concern that a Supervolcano eruption was imminent.
Geothermal activity continued and the Pitchstone Plateau became a lava field once more. While some geologists thought the eruption at Ranger Lake would relieve the pressure, others dismissed it as wishful thinking citing the way Coffee Pots Spring was acting. These were vindicated when a second, conventional volcano began erupting at Coffee Pots days before the Supervolcano finally let loose.
The eruption caused severe earthquakes and blast which killed most people in a 500 mile diameter circle around the epicenter. The sound was heard across the U.S. all the way east to Maine. The immediate states of Wyoming, Montana and Idaho were covered with many feet of ash as were Utah, Colorado, Nebraska and Kansas further out. Ashfall was experienced as far west as California, as far east as Iowa, as far south east as Texas and as far north as the Canadian province of Alberta.
- Eruption, pgs. 12-13.
- Ibid, pgs. 44-45.
- Ibid, pgs. 60-66.
- Ibid, pgs. 102-108.
- Ibid, pgs. 117-120.
- Ibid, pgs. 139-140.
- Ibid, pg. 244.
- Ibid, pg. 191.
- Ibid, pg. 222.
- Ibid, pg. 218.