By Doug Bennett, Updated Mar 24, 2022
Volcanologists use a variety of classification systems to describe volcanoes worldwide. Regardless of the system, three primary types consistently emerge: cinder cone, composite (stratovolcano), and shield volcanoes. Though they share some characteristics, each type differs markedly in structure, size, lava composition, and eruptive behavior.
Cinder cone volcanoes exhibit steep, straight sides ranging from 30° to 40° and a single, prominent summit crater. They are built mainly from tephra—fragmented pyroclastic material. Composite volcanoes have an upward‑concave profile with a small summit crater, constructed from alternating layers of hardened lava and pyroclastic deposits. Shield volcanoes display an upward‑convex slope, typically less than 15°, and a relatively flat summit. Their flanks are dominated by extensive basaltic lava flows emanating from a central vent, vent clusters, or rift zones.
Cinder cones are modest, rarely exceeding 1,000 ft (300 m) in height. Composite volcanoes can rise over 10,000 ft (3 km) and often form towering peaks. Shield volcanoes are wide, typically 20 times taller than their width, producing massive footprints; Mauna Loa and Mauna Kea in Hawaii are the tallest, rising more than 31,000 ft (9.5 km) from the ocean floor.
Composite volcanoes erupt andesitic, dacitic, and rhyolitic lavas—thick, viscous, and gas‑rich—resulting in a low magma supply rate and infrequent eruptions. Shield volcanoes emit basaltic lava, which is hot, fluid, and low in gas; a high magma supply rate leads to frequent effusive eruptions. Cinder cones produce basaltic lava that is gas‑laden; eruptions are limited, and many cones erupt only once during their life cycle.
Strombolian eruptions characterize cinder cones, producing lava fountains that fragment into bombs and ash falling around the vent. Composite volcanoes generate Plinian eruptions, launching towering ash columns, pyroclastic flows, and lahars. Shield volcanoes produce non‑explosive, long‑distance lava flows that travel across their gentle slopes.
