What is the size and shape of a super volcano?

A super volcano is under the earth`s crust so it is very difficult to measure this hot lava but approx it is 10,000 times the size of Mountain 

A supervolcano is a volcano on a massive scale. It is different from a volcano because:
it erupts at least 1,000 km3 of material (a large volcano erupts around 1 km3)
it forms a depression, called a caldera (a volcano forms a cone shape)
a supervolcano often has a ridge of higher land around it
a supervolcano erupts less frequently - eruptions are hundreds of thousands of years apart. Example Yellowstone. Hope I helped;) good luck