Marrakech – New research published in the journal Geophysical Research Letters sheds light on the devastating M6.8 earthquake that struck the High Atlas Mountains in Morocco on September 8, 2023, ending a 63-year seismic silence in the region.
The findings suggest that the earthquake, which caused approximately 3,000 fatalities and affected nearly 2.8 million people, was triggered by a mantle upwelling along a deep fault that offsets the Earth’s crust from the mantle.
The international team of researchers, led by Kai Huang and Guoguang Wei from the Southern University of Science and Technology in Shenzhen, China, utilized advanced techniques such as interferometric radar data, Bayesian inversion, and teleseismic data to pinpoint the origin of the earthquake.
They determined that the seismogenic fault was centered at a depth of 26 km, striking 251° and dipping 72°, closely aligned with the Tizi n’Test fault system.
Remarkably, the earthquake’s hypocenter was located at the depth of the Mohorovičić discontinuity (Moho), the boundary between the Earth’s crust and mantle, at around 32 km.
Joint inversion of radar and teleseismic data revealed that the rupture was concentrated between depths of 12 and 36 km, causing displacement of the Moho.
The researchers propose that the earthquake was possibly triggered by mantle upwelling, a process that also supports the high topography of the Atlas Mountains.
A mantle upwelling can lead to the injection of fluids or magma along pre-existing faults, reducing the threshold for fault failure and resulting in seismic activity in the lower crust.
This groundbreaking study highlights the importance of understanding deep crustal dynamics in assessing seismic hazards, particularly in regions like Morocco, where traditional risk models may not account for such factors.
The findings also emphasize the need for improved seismic monitoring and infrastructure resilience strategies in areas with infrequent but potentially devastating earthquakes.
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