How climate once fueled earthquakes at the cradle of humankind

In northern Kenya, there’s a massive desert lake called Lake Turkana. Scientists know it as something else entirely: one of the most important places on Earth for understanding where we come from.

Its dry basin is filled with fossil clues that have helped us trace our human story back millions of years. Now, scientists say the lake is revealing another side of that story – one that’s not just about bones and artifacts. It’s about the land itself.

Climate shifts move Earth’s crust

For years, the rule in geology was simple: continents break apart because of forces deep below Earth’s crust. That’s called rifting. But researchers now say there’s more to it.

“Continental break-up (‘rifting’) is generally thought of as a process fundamentally rooted in plate tectonics,” explained Chris Scholz, professor of Earth sciences at Syracuse University and co-author of the study.

“Our research shows that rifting is also shaped by surface processes, including regional climate.”

Lake level drives tectonic activity

The team found that when the climate was wetter, Lake Turkana got deeper – more than 350 feet deeper than it is today. That extra water pressed down on the Earth’s surface.

But during drier periods, when the lake got shallower, that weight lifted. And that shift made a difference.

During dry phases, faults beneath the lake moved faster. More magma rose from deep below. In other words, the Earth’s crust got more active just because the water got lower.

“These pressure changes lead to increased melting in hot regions deep in the Earth and also make faulting or earthquakes more likely to occur,” said James Muirhead, senior lecturer at the University of Auckland, who led the research.

Challenges of studying Lake Turkana

Getting this data wasn’t easy. The region is difficult to reach, and the Lake is no picnic either.

“The conditions on Lake Turkana in the northern part of the Kenya Rift were among the most challenging our team has encountered anywhere in the world,” said Scholz.

“The lake is the largest in the world in a desert, is in one of the windiest places in Africa and is extremely remote.”

There’s no coast guard or rescue teams. The research team hauled their boats in by land, then surveyed and collected samples across 27 faults under the lake.

The payoff? Some of the most precise data on fault activity in any rift zone in East Africa.

Unique fault activity data

“Arguably the best estimates on fault activity rates over the past 10,000 years of any rift basin in the East African Rift System,” said Muirhead.

The results lined up with findings from other parts of the world, like Iceland and the western U.S., where losing the weight of glaciers has triggered more fault movement and volcanic activity.

“What was surprising was just how much the rate of faulting can change due to just a few hundred meters of lake level change,” Muirhead added.

“This is likely because rock melting and the generation of magma below the rift further enhances the tectonic response to these lake level changes.”

Early humans felt the shakeup

This shifting Earth didn’t just matter for volcanoes and earthquakes. It also changed life on the surface – especially for early humans.

As the climate shifted and lake levels dropped, those living in the area likely had to deal with more eruptions, more quakes, and more unstable ground. That would have affected access to food, water, and shelter.

“This work reveals a complex environmental backdrop to the landscape occupied by early hominids, early modern humans and recent members of our species,” Muirhead said.

Climate, volcanoes, and earthquakes

These findings matter for today, too. While we won’t see more volcanoes erupt tomorrow because of climate change, over thousands of years, shifts in water levels could still impact what’s happening below our feet.

“Climate change, whether human-induced or not, will likely impact the probability of future volcanic and tectonic activity in East Africa,” Muirhead explained.

“However, these changes occur over geological rather than human timescales, so their effects would be subtle and largely imperceptible within a single lifetime or even across generations.”

But some changes might come sooner. Climate models now predict that Lake Turkana could actually rise again in the coming decades – not shrink.

More rainfall is expected in the rivers feeding it. If that happens, the region could see flooding. And that could shift pressure on the crust again.

Even water projects, like new dams or irrigation systems, could play a role in changing crustal pressure and possibly affecting fault activity.

A new understanding of Earth

This study adds to a growing understanding that Earth’s systems are connected. Tectonic plates don’t move in isolation. Climate, water, and the atmosphere all play a role.

“We are heading towards a more holistic understanding of the processes that drive plate tectonics, and also recognizing the role of plate tectonics in controlling long-term climate and its impact on the evolutionary trajectory of life on our planet,” said Muirhead.

That shift in thinking could help scientists build better models for earthquakes and volcanic risks.

In dry periods, faults might behave differently than in wetter ones. That’s a big deal for places like East Africa, where millions live near active rift zones.

“If I were doing a hazard assessment for a fault line in a continental rift like Turkana, I would need to consider how its rate of activity, and resulting likelihood of an earthquake, is affected by the current climate state and associated lake water volumes,” said Muirhead.

Climate shapes the future of earthquakes

This work shows how Earth’s surface and its deep interior are more connected than we thought. It also reminds us that the climate doesn’t just shape weather.

Climate shapes the land and can change where earthquakes happen and when volcanoes erupt.

And it’s not just ancient history. The choices we make today could impact how the planet shifts tomorrow.

By keeping an eye on both the sky and the ground, scientists are piecing together a more complete picture of our planet – one that could help us prepare for a more stable future.

The full study was published in the journal Scientific Reports.

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