Central American Volcanic Arc

The Central American Volcanic Arc is a chain of volcanoes extending along the Pacific margin from Guatemala to Panama. It forms where the Cocos Plate and, in the south, the Nazca Plate descend beneath the Caribbean Plate.

Middle America Trench: A deep ocean trench marking the subduction boundary along the Pacific margin of Central America. It marks the offshore boundary where the oceanic plates begin descending beneath Central America.
Subduction: The descent of one tectonic plate beneath another at a convergent plate boundary. The arc is a classic landward volcanic chain produced above a subducting plate.
Fuego: An active stratovolcano in Guatemala known for frequent explosive eruptions. Its persistent activity makes it a prominent example of the arc’s ongoing volcanism.
Volcanic ash: Fragments of volcanic rock and glass smaller than two millimeters, expelled during explosive eruptions. Ash from arc eruptions can disrupt aviation, agriculture, and settlements far from a volcano.
Cocos Plate: An oceanic tectonic plate beneath the eastern Pacific Ocean. Its descent beneath Central America supplies much of the arc’s magma-generating system.
Volcanic arc: A curved chain of volcanoes formed above a subduction zone. The Central American chain is one regional example of this global tectonic feature.
Pacaya: An active volcanic complex in Guatemala with a frequently active central cone. Its lava flows and explosive episodes illustrate the range of activity within the arc.
Lahar: A fast-moving mixture of water and volcanic debris flowing down a volcano’s slopes. Rain and eruption deposits can generate destructive flows in the arc’s steep, populated terrain.
Caribbean Plate: A mostly oceanic tectonic plate underlying the Caribbean Sea and parts of Central America. The arc overlies its western margin, where incoming oceanic crust is subducted.
Andesite: A fine-grained volcanic rock with an intermediate silica content, common at convergent margins. Andesitic compositions are characteristic of many volcanoes in the Central American arc.

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