The flow moved northward and eastward from the vent over a terrain with slopes of 3-4°. The flow has a surface area of 11 square kilometres (4.2 sq mi) with a flat circular surface containing flow folds. Steep 200-metre (660 ft) high flanks limit the flow, which has a total volume of 4 cubic kilometres (0.96 cu mi). It is surrounded by a pumice deposit probably from the San Pedro volcano to the northwest.[5]
The eruption of the Chillahuita dome involved the entry of andesitic magma into a pre-existent shallow reservoir.[4] It appears to have been controlled by local fault systems associated with the Altiplano-Puna volcanic complex, which also has geochemical similarity with Chillahuita lavas.[5]
^ abcde Silva, S. L.; Self, S.; Francis, P. W.; Drake, R. E.; Carlos, Ramirez R. (1994). "Effusive silicic volcanism in the Central Andes: The Chao dacite and other young lavas of the Altiplano-Puna Volcanic Complex". Journal of Geophysical Research. 99 (B9): 17805. doi:10.1029/94JB00652. S2CID128766861.