The Erta Ale is an Ethiopian volcano located in the Afar region, at the north east of the country, in the massif of the grand rift valley. The volcano has an altitude of 613 meters for 30 kilometers in diameter basis, which makes it called a “shield”.
We found, at the top of this very active volcano, a caldera that contains two craters. The Pit South crater, of 200 meters in diameter, is currently the most impressive as it contains a permanent lava lake, whose temperature of molten rocks reaches up to 1200 degrees Celsius. The level of the lake varies according to the weather. In January 2017, the lake was so high in the crater that the latter finally overflowed. In April 2017, the level of the lake has gone down offering its observers a great spectacle. Indeed, the surface of the lake was, in April, in perpetual movement and an impressive phenomenon of emptying and re-filling of the lake took place cyclically. This phenomenon can be seen in the video at the end of the article.
Location of the Erta Ale volcano
In the Afar language, « Erta Ale » means « smoking mountains »
From the basis of the volcano, it is possible to see the columns of smoke escaping from the craters. Because of this, the Afar always considered this mountain as “cursed”. This picture also highlights the very flattened form of this volcano called “shield”.
View from the Pit North crater. Behind right we can see the Pit South crater of Erta Ale
The surroundings of the crater form a dramatic landscape.
On the ground, the solidified lava accumulate coming from the craters when they are overflowed.
The visible “cliff” on the picture is actually one of the sections of the caldera.
A caldera can be formed when the inside of the volcano becomes “hollow” after it has rejected a huge amount of lava. Therefore, the top of the volcano collapses under its own weight leaving only the vertical faces called caldera (this Latin word means “Cauldron”). The caldera of the Erta Ale has an oval form measuring 1.6 km by 0.7km.
Here comes the lava lake of the Pit South crater, picture taken by night. In April 2017, when this picture has been taken, the level of the lake was approximately 80 meters from the top of the crater.
Small lava flow
The lava is kept in fusion because it is traversed by extremely hot gases coming from the basement and which rises towards the surface. Those gases create lava flows that are even more impressive when the lava lake is low.
From time to time, the lava lake disappeared inside the volcano before coming back to its original level. On this picture, the Pit South crater has totally disappeared.
The Pit South crater at the end of the day.
On the top right of the picture, an observer could have an idea of the dimensions of the crater.
Some other observers at the edge of the Pit South crater
The lava at the surface of the lake is getting cold and solidifies into dark patches
Details of the lake surface
Another view of the lake surface
Sunset on the Erta Ale
The Toucan on the edge of the Pit South crater
Observation under the stars of the smoke emitted by the volcano
Smoke mixture coming out of the crater
The lake of the crater once emptied. This purge of the lake takes place in just a few minutes.
Close-up look of the bottom of the crater when the lava lake disappeared in the bowels of the Earth.
At this point, the heat felt from the edge of the crater becomes unbearable.
This scene presents a phenomenon of emptying and re-filling the Pit South crater.
This is a 6 times accelerated video in order to make the observation of the phenomenon. Duration: 2 minutes.
Here is the same scene but at the real speed. Duration: 12 minutes.
To read more about the Erta Ale volcano:
Erta Ale on Wikipedia (EN)
Information on Erta Ale from the Global volcanism programm (EN)