EFFECTS OF CINDER-CONE ERUPTIONS ON HUMAN POPULATIONS IN SOUTHWESTERN NORTH AMERICA
Sunset Crater erupted in the San Francisco volcanic field near present-day Flagstaff, Arizona, at ~1050-1100 CE, producing a >300-m-high cinder cone, basaltic lava flows that cover ~8 km2, and a fallout blanket that covers >2000 km2. Little Springs Volcano erupted in the Uinkaret volcanic field north of the Grand Canyon, Arizona, at ~1100-1200 CE. The spatter rampart is ~100 m high, and lava flows cover ~4 km2. There is little cinder fall on the surrounding landscape. Parícutin erupted 1943-1952 CE in Michoacán, Mexico, producing a 424-m-high cinder cone, basaltic lava flows that cover ~25 km2, and a widespread cinder blanket.
Human adaptation to the eruptions differed. Population migration occurred at Sunset Crater and Parícutin. At Sunset Crater, small groups migrated to lower elevations, where a decades-long precipitation increase and newly deposited cinder mulch allowed farming. There was probably little conflict with previous inhabitants, as there appear to have been very few people living in this area prior to the eruption. At Parícutin, five villages were affected, and thousands of people displaced. The Mexican government moved the villagers to new localities, but land disputes with prior residents led to at least 100 deaths. At Little Springs volcano, migration did not occur. Instead, new sites were built at the base of the lava flow, while structures and trails were built on the flow itself, and farming continued where the lava did not cover suitable land. At all three volcanoes, the lava flows are still not farmed. Although these eruptions were small, they dramatically affected the local environment and, hence, human populations.