Disclaimer: I'm no Danish teaching expert, I just happen to be an Icelander who was forced to learn Danish as my second language - and although I always got very good grades in Danish, I was never good in Danish: can't speak it, can't understand a Dane - I can maybe read it a little bit...
University of Utah geology and geophysics professor Fan-Chi Lin said the blob-shaped lower magma reservoir in Earth's lower crust is located 12 to 28 miles (20-45 km) under Yellowstone, with a volume of 11,500 cubic miles (46,000 cubic km), or 11.2 times the volume of Arizona's Grand Canyon.
Areas such as these are known as volcanic hotspots. Occasionally, molten rock from a hotspot will erupt. Three enormous eruptions occurred at the Yellowstone hotspot 2.1 million, 1.3 million, and 640,000 years ago. Two of these released so much material that the area is often referred to as a supervolcano. supervolcano is a volcano that at one point in time erupted more than 1,000 cubic kilometers of deposits. That is enough material to fill up Lake Erie twice; Lake Erie is one of the Great Lakes, and it has a volume of 480 cubic kilometers.