Erta Ale (Ethiopia): summit lava lake revives as activity at flank eruption site slows down

Our Ethiopian expedition organiser Enku made a reconnaissance trip to Erta Ale in September and reported the current status of this continuously changing active volcano. It appears that over summer the lava lake in the summit crater slowly rose and remains very active, but that the fissure eruption at the volcano's south flank (which started during the dramatic change of volcanic activity mid January 2017) slowed down.

The lava lake of Erta Ale's summit caldera is currently at some 75 m below the rim of the south crater, a large circular pit with dimensions of about 230 by 230 m. The lava lake is thereby occupying the northern part of this active crater and strongly degassing, making daytime observations more difficult. However, from sunset throughout the night-time the volcanic gasses periodically clear up so that one can have a clear view onto surface of the active lava lake and observe its constant movement. The thin black surface of the lava lake thereby shows red-hot cracks where liquid lava wells up, pushing the crust sideways and even overflowing and recycling it. Sometimes gasses well up in the liquid lava below the surface and break through it, exploding in large bubbles of lava. The movement of the spreading lava lake crust is steady and strong degassing alternated with clearing up of the view occurs in cycles.


Meanwhile the recent fissure eruption located about 4 km south of the volcano's summit seems to be slowing down after 18 months of vigorous activity. This means that Erta Ale's main activity is once again concentrating on the summit caldera where the lava lake in the south crater is slowly but surely reviving. If this trend continues, we can expect that over the next few months the lava lake will gradually rise, covering more of the bottom of the south pit and becoming better visible as the volcanic gasses can escape more easily.

Depending on how large the magma input below the volcano is, the lava lake may recover relatively fast from its drainage and partial collapse in January 2017 and once again overflow onto the floor of the large summit caldera within a (few) year(s). Although the sudden emptying of the summit lava lake upon the opening of the south flank fissure eruption was an event not previously reported at Erta Ale, the rising and falling of the lava lake's surface with many tens of meters and periodic overflows onto the caldera flow were standard observations throughout the past 2 decades. We should not forget that Erta Ale, like any other active volcano, is constantly changing and its eruptive activity merely the surface expression of the amount of magma rising up from deep below. Volcanoes built up over tens and hundreds of thousands of years, making the decades, or sometimes even centuries, that we observe and document their activity mere moments in their long life.

Those fascinated to experience this volcano's heartbeat at first hand are invited to check out our Danakil volcano adventures. We have 20 years of expertise in organising expeditions to this unique volcanic region and plan multiple days to explore both Erta Ale's summit caldera with the active lava lake and the new fissure eruption site!