Why in news?
Geologists have discovered that long‑term drops in Lake Turkana’s water level have increased the frequency of earthquakes and volcanic activity in the region. The study shows that climate‑induced drying over thousands of years has reduced the weight of water pressing down on the Earth’s crust, allowing underlying faults to slip more easily and magma to rise. This is one of the first pieces of evidence linking climate change to tectonic forces.
Background
Lake Turkana lies in the arid Turkana Basin on the border of Kenya and Ethiopia. It is the world’s largest permanent desert lake and one of the oldest lakes on Earth. Fed mainly by the Omo and Turkwel rivers, the lake formed as the East African Rift opened up millions of years ago. The region is famous for early human fossils and unique wildlife, but is also marked by periodic droughts and fluctuating water levels. Over the past six thousand years the lake has shrunk by up to 150 metres due to climate changes that reduced rainfall and river inflow.
Key findings of the new study
- Climate–tectonic link: By mapping 27 faults beneath the lake using sonar and analysing their slip rates, scientists found that periods of lower lake level correspond to faster fault movement and increased magma production.
- Reduced pressure on the crust: When lake water recedes, the weight pressing down on the Earth’s crust decreases. This reduction in pressure lowers the stress threshold on faults, making it easier for them to slip and release stored energy as earthquakes.
- Magma generation: Lower water levels also allow more magma to accumulate and rise through the crust, increasing the likelihood of volcanic eruptions along the rift.
- Implications: The findings challenge the idea that continental rifting is driven only by deep Earth processes. They suggest that climate‑driven hydrological changes can influence tectonic activity over geological timescales.
About Lake Turkana
- Geography: The lake is about 250 kilometres long and up to 30 kilometres wide, with a salinity similar to seawater. Three volcanic islands—North, Central and South Island—sit within its waters.
- Ecology: It supports crocodiles, tilapia, Nile perch and the world’s largest population of Nile crocodiles. Surrounding semi‑arid plains are home to nomadic pastoralists such as the Turkana people.
- Cultural importance: Fossil finds near its shores, including the famous “Turkana Boy” skeleton, provide key evidence of human evolution.
- Environmental challenges: Reduced rainfall, upstream dam projects and rising temperatures threaten the lake’s water balance. Lower levels affect fishing, grazing and local livelihoods.
Conclusion
The research linking Lake Turkana’s shrinking waters to increased seismic and volcanic activity highlights how climate and geology are interconnected. Protecting the lake’s catchment from overextraction and managing climate change impacts are essential not only for local communities but also for understanding Earth’s dynamic systems.
Sources: Phys.org, Down to Earth