 Cerro Azul has a history of eruptions dating back to at least 1846. The known events include effusive eruptions (lava flows), which created the Quizapu vent, explosive eruptions, and phreatic eruptions. Pyroclastic flows have also been observed as a result of some of these explosive eruptions. The earliest recorded eruption began on November 26, 1846, while the volcano's last eruption began on August 9, 1967. The volcano has produced two of the largest eruptions in South America in recorded history, in 1846 and 1932. Both released 4 – 5 cubic kilometers (1.0 – 1.2 cu mi) of the dacitic magma.
