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The M6.8 earthquake that struck the High Atlas Mountains in Morocco on September 8, 2023, may have been triggered by hot, molten rock rising from deep within the Earth, according to a recent study by scientists from the Southern University of Science and Technology in Shenzhen, China.
The researchers believe that the earthquake, which caused 3,000 fatalities and affected nearly 2.8 million people, was very unusual. It was the strongest in the region since 1960. Typically, large earthquakes occur where tectonic plates meet and push against each other, which was not the case for the Al Haouz earthquake.
Most of Morocco’s seismic activity occurs near the Rif Mountains, to the north of the 2023 epicenter, where the African and Eurasian plates converge. However, the plates near the High Atlas Mountains, where the catastrophic event took place, are converging at a rate of only about 1 millimeter per year.
Mantle upwelling
The study explains that the Middle-Atlas, High-Atlas, and Anti-Atlas ranges are shaped by «mantle upwelling processes». Meaning that the Al Haouz earthquake occurred due to a mantle upwelling, which pushed on the fault and caused it to slip.
The researchers studied the earthquake using an integration of geodetic, seismic, and seismicity data to reveal where it started and how it moved underground. The study shows that it started at a depth of about 26 kilometers on a fault line called the Tizi n'Test fault system.
Mantle upwelling. / Ph. The 2023 Mw 6.8 Morocco Earthquake: A Lower Crust Event Triggered by Mantle Upwelling?
«The 2023 Morocco High Atlas earthquake, a seismic event of magnitude 6.8, stands as an exemplary case in understanding intraplate seismicity under the influence of mantle upwelling», the study reads.
It further explains that this «rare lower crust earthquake, far from plate boundaries and in a region with a low convergence rate, challenges long-standing paradigms of seismic hazard».
The study concludes that such findings help with understanding and improving earthquake prediction, especially in regions that don't typically experience significant seismic activity.
