Global Volcanism Program | Image GVP-07861
A thick sequence of tephra layers, mostly from Acatenango, is exposed on the northern flank. Yepocapa, the northernmost of the two volcanic centers forming Acatenango, formed between about 70,000 and 43,000 years ago. Its major period of eruptive activity ended about 20,000 years ago, after which the activity of the southernmost center, Pico Mayor, commenced.
Photo by Bill Rose, 1987 (Michigan Technological University).