Final answer:
Plate tectonics, involving the movement and interaction of Earth's crustal plates, is the geological phenomenon responsible for the formation of stratovolcanoes like Mount Nyiragongo.
Step-by-step explanation:
The geological phenomenon that contributes to the formation of stratovolcanoes like Mount Nyiragongo is plate tectonics. This process involves the movement of the Earth's crustal plates, which can lead to earthquakes, volcanic eruptions, and the creation of mountain ranges. Stratovolcanoes are typically found at convergent plate boundaries where one plate subducts beneath another, causing magma to rise and solidify as it reaches the surface, eventually forming the layered structure characteristic of stratovolcanoes. Mount Nyiragongo, located in the Democratic Republic of the Congo, is a result of the African Plate's movement over a hotspot, leading to its frequent and notable eruptions.