History of Volcanic Activity
Yellowstone National Park is part of the largest active volcanic systems. Many of the geologic features at Yellowstone are connected with the fact that the park lies on a 'hot spotí. The volcanic activity of Yellowstone's past was from caldera eruptions, which are giant explosions with violence, noise and enormous destruction.
This diagram shows the 'track' of the Yellowstone 'hot spot' Source: PowerPoint Presentation, Lori Snyder, Department of Geology, University of Wisconsin- Eau Claire
Volcanic History and Recent Seismic Activity in the Yellowstone region
The diagram above shows how active this region is and where the previous caldera volcanoes were located. Source: http://pubs.usgs.gov/fs/2005/3024/
The first eruption, the Huckleberry Ridge eruption is said to have erupted 2.1 million years ago and the debris from that volcano reached as far as the Iowa and central Texas.
At Golden Gate, above, deposits from the Huckleberry Ridge eruption can be observed. It is located 20 km north of the rim of the caldera. Source: http://volcanoes.usgs.gov/yvo/images/20010523-172-srb_med.jpg
The second eruption was 1.3 million years ago, the Mesa Falls eruption covered a smaller expanse but did produce the Henrys Fork caldera near Island Park.
This ash-flow was exposed near Ashton, Idaho and was deposited from the eruption of Mesa Falls eruption. Source:http://volcanoes.usgs.gov/yvo/images/19830714-dz-0099_med.jpg
The most recent eruption of Yellowstone, the Lava Creek eruption, was 630,000 years ago and it covered nearly 1000 km cubed, and reached as far as Louisiana and California.
Lava Creek Tuff is exposed on the scarp. Source: http://volcanoes.usgs.gov/yvo/images/2001-rim-rbs_med.jpg
Diagram of Yellowstone Caldera Eruption Areas
This diagram shows the range of each eruption thanks to geological evidence found in the different regions. Source: www.earthmountainview.com/. ../Yellowstone. tm
This diagram shows the magnitude of the eruptions at Yellowstone compared to other large eruptions. Source: http://serc.carleton.edu/research_education/yellowstone/volcanic_hazard.html