A drying climate is making East Africa pull apart faster
Over the past 5,000 years, East Africa has dried out. Now, new research reveals that this shift could accelerate the fracturing of the continent.
Faults in the East African Rift Zone have accelerated since the level of the Great Lakes fell, according to a study published in November in the journal Scientific reports.
“Usually we think the opposite: mountains build and that changes the local or regional climate,” Scholz told Live Science. “But it can also work the other way.”
Scholz and his colleagues conducted their research on Lake Turkana in Kenya, which is 250 kilometers long, 30 km wide and up to 120 meters deep in places. However, this is nothing compared to the level more than 5,000 years ago, when the lake was up to 150 meters deeper.
This was during the African Humid Period, when much of Africa was wetter than it is today. In East Africa, this period persisted from about 9,600 years ago until 5,300 years ago, with drier conditions over the last 5,300 years. Researchers studied lake bed sediments to determine ancient water levels and sediment fluxes in Lake Turkana. In doing so, they noticed many small faults and the fingerprints of ancient earthquakes in the sediments.
The tectonic plate that underlies Africa is breaking apart in East Africa and could one day split into two plates separated by an ocean. The region’s deep, narrow lakes – notably Lake Turkana and neighboring waterways, such as Lake Malawi in Tanzania and Mozambique – are the result of this rifting process, which creates a deep valley in the region.
Scholz and his team wanted to know whether changes in the lakes themselves influenced this rupture process. Water is important for tectonics: when glaciers retreat, for example, the lifting of their weight actually causes the land below to rise up like rising bread – a process called isostatic rebound. Large amounts of water also put pressure on the crust below, potentially affecting processes such as earthquakes.
The researchers found that after the African Wet Period ended, the Lake Turkana faults began to move more quickly, at an average rate of 0.007 inches (0.17 millimeters) of additional movement per year. In general, Africa is tearing itself apart at 0.25 inches (6.35 millimeters) per year.
Using computer simulations, the researchers found that this seismic acceleration likely had two causes. The first is that with less water pressing on the crust, the faults have more freedom of movement: imagine a vice loosening around two plates of wood. The other cause is more indirect. On an island on the south side of Lake Turkana there is a volcano with an active magma chamber. Removal of water from the African Wet Period decompresses the mantle beneath this volcano, leading to even greater melting. This melt, in turn, moves into the volcano’s magma chamber, inflating it and causing more tectonic activity on nearby fault lines.
“We see increased faulting during this time interval, so more pronounced earthquakes are likely prevalent in this larger region today than 8,000 years ago,” Scholz said.
Researchers are currently working on a project on Lake Malawi that studies water level changes dating back 1.4 million years, hoping to get a better idea of how climate affects the separation of continents.
“This information about these huge changes in the water volumes of these lakes is a very important part of the story,” Scholz said.
Muirhead, JD, Xue, L., Moucha, R., Paciga, MK, Judd, EJ, & Scholz, CA (2025). Accelerated rifting in response to regional climate change in the East African Rift System. Scientific reports, 15(1), 38833. https://doi.org/10.1038/s41598-025-23264-9
