 As with the majority of the Andean volcanoes , Cerro Azul is a stratovolcano , meaning that it consists of layers , or strata , of volcanic ash and lava flows . The cone of Cerro Azul has a total volume of about 11 cubic kilometres ( 3 cu mi ) , and is a young feature , formed in the Holocene . It is made of agglutinated pyroclasts and some dacite – andesine lavas . The cone has a few volcanic craters ; the majority of its eruptions in recorded history have originated from Quizapu Crater on the northern flank of Cerro Azul 's cone . Other craters lying on the flanks of the main cone are Caracol ( " Snail " ) , Crater los Quillayes , Crater la Resolana , and Crater sin Nombre ( " Nameless Crater " ) . All of the craters lie between 2 @,@ 000 and 3 @,@ 000 metres ( 6 @,@ 600 and 9 @,@ 800 ft ) in elevation , except Quizapu , which is 3 @,@ 292 metres ( 10 @,@ 801 ft ) up the volcano . The summit of Cerro Azul is crowned by an asymmetric crater about 500 metres ( 1 @,@ 640 ft ) in diameter . Pleistocene glacial activity is evident in the form of 500 meter ( 1 @,@ 640 ft ) deep struts in the volcanoes ' sides . These deep cuts have revealed strata of older rock . 
