Final answer:
The El Chichón volcanic eruption was primarily caused by the subduction of the Cocos Plate beneath the North American Plate, a process characteristic of the complex tectonic activity in the Pacific Ring of Fire region in Mexico.
Step-by-step explanation:
The El Chichón volcanic eruption in Mexico was influenced by the complex interactions of multiple tectonic plates beneath the country. Mexico is situated on top of the North American Plate, but it is also near the boundaries of the Cocos Plate and the Caribbean Plate. The subduction of the Cocos Plate beneath the North American Plate creates significant geological activity, leading to the formation of volcanic features such as El Chichón. The internal heat generated by tectonic movements along these boundaries results in the melting of the mantle and crust, which can trigger volcanic eruptions.
In addition to plate boundaries, Earth's features like hotspots contributed to the volcanic activity. However, in the case of El Chichón, it is the subduction of the Cocos Plate that is primarily responsible. This process is part of the larger Pacific Ring of Fire, where many of the world's volcanic eruptions and earthquakes occur due to plate movements. The morphology and layout of Mexico's topography, including the Sierra Oriental and the Mexican Plateau, illustrate the geological forces at work.