The landscape is characterized by ridges, valleys and small volcanoes. Approximately 26 small volcanoes have been identified at Pasto Ventura, including 14 volcanic cones, seven volcanic domes, two maars and three tuff rings; one isolated lava flow linked to an eruption fissure has been reported and additional volcanoes may exist but are buried under lava. None of these volcanoes has a volume exceeding and the total volume reaches only , making them small edifices by the standard of the Puna. The frequency of volcanic landforms per unit area is also low with only seven vents every .