2. The Hot Spot
• Hot spot track
– History of eruption
– Magma sticky
continental
– Makes larger
eruptions
3.
4. • Magma rises through continental crust
• When pressure exceeds rock strength and weight an
eruption will occur
• This magma chamber is also very shallow at 2 miles deep
5. Future?
• Shallow magma
chamber
• Still being fed from
below
• Another eruption
will happen
• Cannot predict when
Editor's Notes
Yellowstone supervolcano is one that we watch very carefully. It is a hot spot, so it has a constant source of new material coming up from below. It’s also classified as a supervolcano because it has the potential to eject over 1000 cubic kilometers of debris into the air. It has a shallow magma chamber, which is also the source of heat for the many geysers found in the area. This volcano will erupt again, and we hope we are not here when it happens.
Yellowstone’s history is outlined in its eruption track, seen in this diagram. Hot spots are persistent features that are generally stationary. They leave their mark on the plate as it rides above the hot spot. In the case of Yellowstone, the hot spot is coming up under continental crust, which makes a much stickier and explosive magma.
This map shows the relationship between the Snake River Plain, and previous eruptions of Yellowstone. Notice the locations of the earlier eruptions down the path of the plain, otherwise surrounded by mountains. This is due to caldera style eruptions.
Calderas form because of the amount of material ejected leaving a hole. Whatever is left sinks down, leaving a very large hole at the surface.
This is the Yellowstone magma chamber. It’s very shallow, and very big. The crust itself is about 25-30 miles thick, but the vertical on this diagram is much deeper than that. Notice there is some vertical exaggeration. This volcano will blow again some day, but predicting it more than a few days to weeks ahead is not possible. When we look at the history of eruptions, we can determine an average interval of recurrence. However, it is just an average, and not necessarily precise.
