 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 . 
