In the Horn of Africa, the vast peninsula occupied by Somalia, Djibouti, Eritrea and Ethiopia, a geological transformation is underway that could radically change the map of the Earth.
And in the hot and extraordinarily dry region of the Afar depression, tectonic dynamics prepare the formation of a new ocean. A phenomenon that reminds us of the impressive power of the forces of nature that shape our planet.
The land is torn apart in the Afar depression
In the Afar Depression, also called the Afar Triangle, the Great African Rift begins, a huge fault 4,830 kilometers long which extends to Mozambique and crosses ten countries.
At this place three tectonic plates converge: the African, the Somali and the Arabian. The point where they meet is called the “triple junction”. This is why what is known in geology as tectonic rifting occurs.
A phenomenon which, associated with intense volcanic and seismic activity, causes the thinning and fracture of the earth’s crust. This results in a slow but progressive separation of the tectonic plates, at a rate of 2.5 centimeters per year.
A notable example of this activity occurred in 2005. Following a series of severe earthquakes, a huge fissure 60 kilometers long has opened near the Dabbahu volcano in Ethiopia.
An event of this magnitude would normally have taken centuries to unfold. However, it occurred within a few days, demonstrating to what extent, in this region, the ground is torn from the depths.
Currently, a significant seismic swarm is precisely recorded in the area, leading to the appearance of large cracks. In a few hours, several jets of gas, rocks and mud have been observed near the Fentale volcano.
The Geological Survey of Ethiopia has confirmed the presence of warning signs of an eruption. Currently, thousands of civilians from this remote region of northeastern Ethiopia are evacuated due to increased seismic and volcanic activity.
The birth of a new ocean, sooner than expected
According to specialists from the Geosciences Laboratory at the University of Montpellier, in France, the rifting process underway in the Afar depression could lead to the formation of a new ocean.
Scientists explain that as tectonic plates continue to move apart, cracks in the Earth’s crust widen and fill with magma from the Earth’s mantle. This magma will eventually solidify, forming new ocean crust.
Over time, the Red Sea and Gulf of Aden could flood the region, forming a new ocean and resulting in the separation of the Horn of Africa from the rest of the African continent.
And when will this happen? Although initial predictions indicated that this new ocean would take between 8 and 10 million years to form, new studies by geologists suggest that it could happen in just a million years.
A tectonic process similar to the creation of the Atlantic
The ongoing tectonic rifting phenomenon in the Afar depression is similar to that which gave birth to the Atlantic Ocean.
About 200 million years ago, the supercontinent Pangea, which included all the land masses on the planet and was surrounded by a vast ocean called Panthalassa, began to fracture.
This occurred during the Jurassic period, due to convection currents in the Earth’s mantle which generated stress in the lithosphere (the rigid outer layer of the Earth), causing the formation of fissures and the start of a continental rifting process.
Initially, the separation of North America and present-day Africa occurred, after the creation of a new oceanic crust which, once submerged, marked the birth of the North Atlantic.
As the rifting continued, an underwater chain (the Mid-Atlantic Ridge) emerged in the central Atlantic through the constant formation of new oceanic crust. Thus, the Atlantic Ocean began to expand, filling with the waters of the Panthalassa, until the separation between Africa and South America occurred.
A process of expansion that continues today: the Atlantic continues to widen by around 2 to 4 centimeters per year, under the influence of tectonic plates.
Article reference:
Alemayehu, Sisay & Aoudia, Abdelkrim & Ayele, Atalay & Pachhai, Surya & Ebinger, C. J. & Thapa, Hari & Kherchouche, Radia & Guidarelli, Mariangela & Kim, Seongryong. (2023). Structure of the Crust-Uppermost Mantle Beneath the Ethiopian Volcanic Province Using Ambient Seismic Noise and Teleseismic P Wave Coda Autocorrelation. SSRN Electronic Journal. 10.2139/ssrn.4314889.
