What geological process is exemplified by Hawaiian islands?

The geological process exemplified by Hawaiian islands is island building occurring over a hot spot. This process occurs when a magma plume from deep within the Earth's mantle rises and breaks through the oceanic crust, resulting in the formation of volcanic islands. As the tectonic plate above the hot spot moves, it can create a chain of islands. The Hawaiian islands are particularly well-known for this phenomenon, having formed as the Pacific Plate moved over a stationary hot spot.

This process is distinct from the other choices. Tectonic plate collisions primarily result in mountain formation or earthquakes, rather than volcanic island chains like those of Hawaii. Coral reef development occurs in warm, shallow ocean waters but is unrelated to volcanic activity and island formation. Erosion of ancient mountain ranges involves the wearing down of landforms over time, which is also different from the volcanic activity that creates islands. Thus, the correct identification of Hawaiian islands as the result of a hot spot is directly linked to the geological understanding of volcanism and plate tectonics.