While it was suspected that a mantle plume lies underneath the Afar region, little was known about its characteristics.
New research, led by the University of Southampton, has uncovered how the molten mantle beneath the Earth’s surface makes it way up more rapidly in regions where tectonic plates are rifting at a faster rate.
Recently published in Nature Geoscience, the study found that molten mantle beneath the Afar region, situated in Ethiopia, pulses upward like a beating heart – but at a much slower rate.
This movement is influenced by tectonic plates that are pulled apart in rift zones over the course of millions of years. The moving plates stretch thin until they rupture, making way for the molten mantle to flow up and create a new ocean basin.
Lead author of the study Dr Emma Watts conducted the study at the University of Southampton.
Watts said that the mantle beneath Afar is not uniform, and that the pulses carry “distinct chemical signatures”.
The Afar region showcases a rarity on Earth, where three tectonic rifts converge. This includes the Main Ethiopian Rift, the Red Sea Rift and the Gulf of Aden Rift.
While geologists have long suspected that the upwelling of the mantle – also known as a plume – lies beneath this region, little was known about how the structure of the upwelling or how it behaves beneath rifting plates.
To find out more, scientists collected more than 130 volcanic rock samples from across the Afar region and the Main Ethiopian Rift. Most volcanoes are formed at convergent boundaries of tectonic plates.
Using these samples, along with existing data and advanced statistical modelling, they found that the Afar region is a single, asymmetric-looking plume with distinct chemical bands that repeat across the rift system, like a “geological barcode”, according to the scientists.
Moreover, the chemical striping suggested that the plume pulses. They also found that the pulses appear to behave differently depending on the thickness of the plates and how fast they pull apart. Tectonic plates move at a very slow place, at just a few centimetres every year.
As discovered by the study, the plumes travel more efficiently and regularly in areas of faster-spreading rifts such as the Red Sea. It is believed that the study has “significant” implications for understanding volcanism, earthquakes and the life cycle of continents.
According to the scientists, this is the first time geochemical and geophysical data were analysed statistically using advanced computer modelling. Dr Emma Chambers, a research fellow at the School of Cosmic Physics in Dublin Institute for Advanced Studies (DIAS), facilitated and processed geophysical data for the study.
Combining expertise from a range of fields is essential in piecing together the full picture, she said.
“The research improves our understanding of the Earth and provides a better understanding of volcanic hazards in the Afar region, helping policymakers mitigate against these to the benefit of the local people of Afar,” Chambers said.
“It will also be beneficial to the scientific community with new methodologies and information about how deep Earth influences surface processes and could help how scientists understand volcanic activity now and in the future.”
The project involved experts from 10 institutions, which included Swansea University, Lancaster University, the Universities of Florence and Pisa, Addis Ababa University in Ethiopia, the GFZ Helmholtz Centre for Geosciences, and Geomar, a research institute based in Kiel, Germany.
Earlier this year, researchers from the University of St Andrews in Scotland finally found out when one of Earth’s largest known volcanic eruptions occurred.
By analysing microscopic ash particles in polar ice cores, the team figured out that the Los Chocoyos super-eruption at the Atitlán volcanic system in Guatemala occurred around 79,500 years ago.
According to researchers, the study was an important step to understanding the risks posed by super-eruptions and their role in climate tipping points.
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Updated, 5.21pm, 3 July 2025: This article was amended to clarify that Dr Emma Watts was lead author of the study.
