Researchers have revealed a strong link between climate change in East Africa and the accelerating rifting of the continent, suggesting that long-term drought could reshape the region’s geological landscape.
The study found that the rate of faulting along the East African Rift has increased since the water levels of major lakes, especially Kenya’s Lake Turkana, began to fall.
Christopher Schultz, lead author and professor of geology and geophysics at Columbia University, said the findings highlight a two-way relationship between climate and tectonic plate movement. He added that the influence does not flow only from geology to climate, but can also move in the opposite direction.
Researchers focused on Lake Turkana, which stretches about 250 kilometers in length and 30 kilometers in width. The lake currently reaches depths of up to 120 meters in some areas. However, water levels were significantly higher more than 5,000 years ago, when the lake reached depths of around 150 meters.
This was during the African Humid Period, which lasted in East Africa from roughly 9,600 to 5,300 years ago. The region was far wetter than it is today before entering a prolonged drought that lasted thousands of years.
By analysing sediment deposits at the lakebed, scientists were able to determine past water levels and sediment flows. They also identified evidence of small faults and ancient earthquakes, providing clear proof of increased tectonic activity.
East Africa’s tectonic plates are gradually pulling apart, a process that could eventually split the continent into two plates separated by an ocean. Deep, narrow lakes such as Turkana and Malawi are among the most visible outcomes of this ongoing geological transformation.
The research team sought to understand whether changes in water levels could affect the pace of rifting. They noted that water plays a key role in applying pressure to Earth’s crust, similar to how glacial melting leads to crustal rebound.
The results showed that after the end of the African Humid Period, fault movement accelerated by an additional 0.17 millimetres per year. The overall rift rate in Africa is about 6.35 millimetres per year.
Using computer simulations, researchers concluded that the acceleration is linked to reduced water pressure on the crust, allowing faults greater freedom to move. They also identified an indirect effect tied to volcanic activity south of Lake Turkana.
As water levels dropped, pressure on the mantle beneath an active volcano eased, increasing melting rates and the flow of magma into the volcanic chamber. This, in turn, boosted tectonic activity in surrounding areas.
“We see a clear rise in fault activity during this period, suggesting that earthquakes became more widespread than they were eight thousand years ago,” Schultz said.
The team is now studying water level changes in Lake Malawi over 1.4 million years to gain deeper insight into climate’s impact on continental breakup.
“These data are essential for building a complete picture of the relationship between climate and Earth’s geological structure,” Schultz added.
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