The volcano is one of the most active in the Galapagos, with the most recent eruption beginning on 26 June 2018, only ten days after a nearby Volcano, La Cumbre, also began erupting. The previous eruption began on 22 October 2005 and ended on 30 October 2005. That eruption was estimated to have produced 1.5x108 m3 of lava. Despite the GPS monitoring on Sierra Negra there was no advance warning of the eruption. There had been expansion of the caldera floor since 1992 but no short term deformational signal was noted before the eruption. Contraction continued through the nine-day eruption before starting again immediately after the eruption ended.