The caldera has an almost perfectly circular outline with the exception of the southwestern margin which is cut by a wide lava dome. This dome is also known as Cerro Blanco or Cerro Blanco del Robledo and reaches a height of above sea level. Three additional lava domes surround this dome, and an explosion crater lies to its southwest. West of this crater there are three pinkish lava domes lined up in west-southwest direction away from the main dome; these are surrounded by pyroclastic cones and depressions.