A second cycle of volcanic eruptions, known as the Roque Nublo cycle, took place between 4.5 and 3.4 million years ago. This shorter cycle emitted about . Most of the inland peaks were formed by erosion from these materials. This period also started with fissural basalts, but ended with violent eruptions of pyroclastic flows. Some phonolitic features, like the Risco Blanco, were also formed in its last stages.