Towards the center of the caldera, hot springs including Cajon Los Calabozos and Baños de Llolli are present. The springs are as old as 0.3 mya, and may have formed directly after Calabozos's second eruption as a result of uplift caused by re-occurring activity in the caldera. The vents occur in two clusters, Colorado and Puesto Calabozos, and are located along the margin of a fault at the southwestern edge of the caldera. Hildreth et al. (1983) evaluated that Calabozos could potentially be useful for the harvesting of geothermal energy.