Final answer:
The modern volcanism at Yellowstone is associated with a hotspot, which is a plume of exceptionally hot mantle material rising beneath the North American continental crust.
Step-by-step explanation:
The modern volcanism at Yellowstone National Park is associated with a hotspot. This is not a typical feature of a subduction zone, rift tectonics, meteorite impacts, or glacial activity. Instead, a hotspot is an area where unusually hot rock from the mantle rises towards the Earth's surface, melting the crust and leading to volcanic eruptions.
Comparing the Yellowstone hotspot to the Anahim hotspot, we can observe different scales of volcanic activity. The Yellowstone hotspot has experienced more significant volcanism, as evidenced by the size of the calderas formed and the volume of eruptive material, especially from some of the largest eruptions such as the Gray's Landing eruption millions of years ago.