Final answer:
A fast change that occurs as a result of plate tectonics is a volcanic eruption.
Step-by-step explanation:
One fast change that occurs as a result of plate tectonics is a volcanic eruption. When two tectonic plates collide, one may sink below the other, creating a subduction zone. The sinking plate can eventually melt, leading to the formation of magma chambers beneath the Earth's surface. When the pressure becomes too high, the magma erupts through volcanoes, resulting in a volcanic eruption.
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