Yellowstone Supervolcano By Jackson Smith Type of Volcano

Yellowstone Supervolcano By: Jackson Smith

Type of Volcano • The Yellowstone caldera is a SUPERVOLCANO! • The Yellowstone Supervolcano is still very active, but is not shooting out lava. • It’s considered a Supervolcano because there is a much larger amount of magma in the magma chamber. • The magma chamber is 40 by 80 kilometers and it sits in the middle of a continental plate. • This is called a Hot Spot.

Instead, Yellowstone’s magma chamber heats the water and rock above it causing pressure to build. This pressure is released in the form of thermal features such as hot springs, mud pots, fumaroles, (steam vents) and geysers!

Size of the Yellowstone Caldera • The caldera formed when the explosive blast from the magma chamber caused the surface of the earth to collapse in on itself. Magma was blown out and the earth collapsed. caldera rim • The caldera is about the size of Rhode Island measuring 65 km wide, 80 km long, and hundreds of kilometers deep.

Geographic Location • Yellowstone is located inside Yellowstone National Park. • The caldera rim is located in Wyoming with only a small portion in Idaho and Montana.

Nearest Cities to Yellowstone • Since the caldera sits inside a national park, permanent homes are not located nearby. • West Yellowstone, MT is the nearest city to the rim. It is approximately 18 -20 miles from the caldera’s edge. • Other major towns are all outside the park. (Gardiner, MT; Cooke City, WY)

Population • West Yellowstone is a small gateway community with only about 1, 271 people living there. (data 2010)

Most Recent and Most Destructive Eruption Information • Yellowstone has been erupting for 2. 1 million years. • The first eruption was 2, 500 times MORE powerful than Mt. St. Helens. • Scientist believe it could possibly be the largest, most violent eruption in history. • Debris from the first eruption covered a large portion of the U. S. in 4 feet of ash. (Huckleberry ridge ash bed) • Three cataclysmic eruptions have occurred since. • Yellowstone’s most recent eruption was around 640 thousand years ago.

Ash Fall Compared with Long Valley and Mt. St. Helens

• The most recent explosive eruption from Yellowstone was 640 thousand years ago. • The three major eruptions spewed enough ash and debris to fill the grand canyon! • About 80 smaller non-explosive eruptions have taken place since then. ØMany were small basalt and rhyolite lava flows (see pictures on the next slide)

Basalt columns were created during the last explosive eruption. Here, you can see evidence from two explosive eruptions. One eruption left columns. Another eruption left a layer of smaller debris.

Sheepeater’s Cliff was formed by steady flow of basalt in a nonexplosive lava flow.

Obsidian Cliff This area inside the caldera is a two mile long rocky hillside made almost entirely of obsidian. It was formed when hot lava came in contact with a glacier.

Events Associated with Past Eruptions Past eruptions have caused: Ø About 650 cubic miles of ash and debris was thrown into the air after the first eruption. Ø Made huge ash clouds that stretched all the way to Oklahoma Ø Buried the state of Wyoming in 3 feet of ash Ø One possible cause of the Ice Age

Earthquakes of the Region The Hebgen Lake Earthquake of 1959 was 7. 3 on the Richter scale. Ø It killed 28 people and did $11 million in damage to roads and timber in an area north of West Yellowstone. • Ø An avalanche with a huge amount of rocks, soil, and trees, fell into the Madison River. • After this earthquake, the park service noticed swelling in the ground inside the caldera. • New geysers began to erupt as well. • This was evidence that the volcano is not dormant.

Facts about the Yellowstone Supervolcano • There about 10, 000 thermal features in Yellowstone and most of them are inside the rim. • Magma is usually 40 miles below the surface but the magma under Yellowstone is approximately 2 miles below the surface. • 86% of rock in Yellowstone is volcanic and the rest is sedimentary

Facts about the Yellowstone supervolcano • Magma Chamber Crust above Magma chamber

Websites and Resources Websites: • http: //volcanoes. usgs. gov/volcanoes/yellowstone_sub_page_54. html • http: //www. city-data. com/city/West-Yellowstone-Montana. html Other Resources: • • Brad Bulin, Instructor for the Yellowstone Association Institute Zack Pennington, Geologist and Instructor for the Yellowstone Association Institute Dr. Charles Amlaner, Kennesaw State University Hope Smith, Kennesaw State University’s Yellowstone Teacher Project