Yellowstone has long been known to be volcanicly active. However, it wasn't until the last few decades, that we found out just how active it is. For years scientists were puzzled because they couldn't find any cauldera (the familiar volcano shape we all know) in the landscape. It wasn't until NASA conducted its early satellite mapping experiments, and a helpful technician thought it might be nice to pass on some of the aerial images to park officials, that it was realised that Yellowstond itself is basically the cauldera.
Scientists have revealed that Yellowstone Park has been on a regular eruption cycle of 600,000 years. The last eruption was 640,000 years ago…so the next is overdue. The next eruption could be 2,500 times the size of the 1980 Mount St. Helens eruption. Volcanologists have been tracking the movement of magma under the park and have calculated that in parts of Yellowstone the ground has risen over seventy centimeters this century.
The most recent caldera-forming eruption about 650,000 years ago produced ground-hugging flows of hot volcanic ash, pumice, and gases that swept across an area of more than 3,000 square miles. When these enormous pyroclastic flows finally stopped, they solidified to form a layer of rock called the Lava Creek Tuff. Its volume was about 240 cubic miles (1,000 cubic kilometers), enough material to cover Wyoming with a layer 13 feet thick or the entire conterminous United States with a layer 5 inches thick. Fine volcanic ash that fell downwind from the eruption site blanketed much of North America. This ash layer is still preserved in deposits as far away as Iowa, where it is a few inches thick, and the Gulf of Mexico, where it is recognizable in drill cores from the sea floor.
POD - On 25 September 1998 the Yellowstone Supervolcano erupts. While there was a detectable increase in seismic activity in the months prior to the eruption, it was not conclusive, and the scientists and officials at both a local and national level did nothing other than draw-up some local evacuation plans and hold meetings.
The entire continental US is covered in thick ash, and global temperatures are going to drop for the next few years.
What happens?
Scientists have revealed that Yellowstone Park has been on a regular eruption cycle of 600,000 years. The last eruption was 640,000 years ago…so the next is overdue. The next eruption could be 2,500 times the size of the 1980 Mount St. Helens eruption. Volcanologists have been tracking the movement of magma under the park and have calculated that in parts of Yellowstone the ground has risen over seventy centimeters this century.
The most recent caldera-forming eruption about 650,000 years ago produced ground-hugging flows of hot volcanic ash, pumice, and gases that swept across an area of more than 3,000 square miles. When these enormous pyroclastic flows finally stopped, they solidified to form a layer of rock called the Lava Creek Tuff. Its volume was about 240 cubic miles (1,000 cubic kilometers), enough material to cover Wyoming with a layer 13 feet thick or the entire conterminous United States with a layer 5 inches thick. Fine volcanic ash that fell downwind from the eruption site blanketed much of North America. This ash layer is still preserved in deposits as far away as Iowa, where it is a few inches thick, and the Gulf of Mexico, where it is recognizable in drill cores from the sea floor.
POD - On 25 September 1998 the Yellowstone Supervolcano erupts. While there was a detectable increase in seismic activity in the months prior to the eruption, it was not conclusive, and the scientists and officials at both a local and national level did nothing other than draw-up some local evacuation plans and hold meetings.
The entire continental US is covered in thick ash, and global temperatures are going to drop for the next few years.
What happens?
