Andahua Volcanoes

The Andagua volcanic field fills a long, narrow valley in southern Peru with cinder cones, lava domes and lava-flow fields. The Valley of the Volcanoes stretches about sixty kilometres and descends toward the Colca River, with high mountains flanking its floor. Most vents lie within the valley or on its sides, their alignment following faults in the landscape. Activity spans the Pleistocene and Holocene. Chilcayoc Grande erupted between 1451 and 1523, and the youngest event, at Chilcayoc Chico, is dated to about 1650.

Lava has repeatedly altered drainage. Flows dammed watercourses to create Chachas, Mamacocha and Pumajallo lakes, while the Andagua River cut a gorge through some barriers and disappeared beneath flows elsewhere for more than sixteen kilometres. Lava affected pre-Inca farmland and later destroyed two towns. The valley's ichu grass, shrubs and terraced fields occupy different elevations, and the lakes form local oases.