Andean natural region
The Andes mountains form the most populated region of Colombia and contain the majority of the country's urban centers. They were also the location of the most significant pre-Columbian indigenous settlements. Beyond the Colombian Massif in the south-western departments of Cauca and Nariño, the Colombian Andes divide into three branches known as "cordilleras" (from the Spanish for "mountain range"): the West Andes run adjacent to the Pacific coast and is home to the city of Cali. The Central Andes run up the center of the country between the Cauca and Magdalena river valleys (to the west and east respectively) and includes the cities of Medellín, Manizales and Pereira. The East Andes extend northeast towards the Guajira Peninsula, and includes the cities of Bogotá, Bucaramanga and Cúcuta.
Andean Volcanic Belt
The Austral Volcanic Zone (AVZ) is a volcanic arc in the Andes of southwestern South America. It is one of the four volcanic zones of the Andes. The AVZ extends south of the Patagonian Volcanic Gap to Tierra del Fuego archipelago, a distance of well over 600 mi (1,000 km). The arc has formed due to subduction of the Antarctic Plate under the South American Plate. Eruption products consist chiefly of alkaline basalt and basanite. Volcanism in the Austral Volcanic Zone is less vigorous than in the Southern Volcanic Zone. Recorded eruptions are rare due to the area being unexplored well into the 19th century; the cloudy weather of its western coast might also have prevented sightings of eruptions. The Austral Volcanic Zone hosts both glaciated stratovolcanoes as well as subglacial volcanoes under the Southern Patagonian Ice Field.