The Gulf of Suez, previously considered a "failed" rift, is still slowly extending at about 0.5 mm/year (≈0.02 in/yr), according to a study in Geophysical Research Letters. Researchers used topography, river-profile analysis and raised coral terraces (up to ~60 ft/18.5 m) along the 300 km rift to infer continued, low-rate rifting. The findings suggest rifts can decelerate rather than simply succeed or fail, and they raise questions about earthquake risk in regions thought tectonically quiet.
Gulf of Suez Is Still Slowly Widening — New Study Shows Rifting Continues 5 Million Years After It Was Thought to Stop
The Gulf of Suez, previously considered a "failed" rift, is still slowly extending at about 0.5 mm/year (≈0.02 in/yr), according to a study in Geophysical Research Letters. Researchers used topography, river-profile analysis and raised coral terraces (up to ~60 ft/18.5 m) along the 300 km rift to infer continued, low-rate rifting. The findings suggest rifts can decelerate rather than simply succeed or fail, and they raise questions about earthquake risk in regions thought tectonically quiet.
07:09 AM, 11/18/2025Science
New research shows the Gulf of Suez — long classed as a "failed" rift — is still extending, albeit very slowly. A paper published Nov. 3 in Geophysical Research Letters reports measurable separation along the rift at roughly 0.5 millimetres per year (≈0.02 inches/year), challenging the idea that rifting in the region completely ceased about 5 million years ago.
Background
About 28 million years ago the Arabian plate began rifting away from Africa, opening what is now the Gulf of Suez. The traditional view holds that this rifting largely stopped ~5 million years ago when plate motions shifted and tectonic activity migrated toward the Dead Sea region. That change left the Gulf of Suez as a gulf rather than a full ocean basin.
New Evidence and Methods
The research team, led by David Fernández-Blanco of the Chinese Academy of Sciences' Institute of Deep‑Sea Science and Engineering, re-examined the rift along its roughly 186-mile (300 km) length. They combined geomorphic analysis — including topography and river profiles that cut through bedrock — with measurements of raised coral terraces that originally formed near sea level during warm interglacial periods and now stand up to about 60 feet (18.5 metres) above present sea level.
"We believe our work fundamentally changes how we think about rift evolution," Fernández-Blanco said. He argues the common binary view of rifts (they either succeed or fail) overlooks a middle path in which rifting decelerates without fully stopping.
Findings and Interpretation
By combining the landscape and reef elevation evidence, the authors infer ongoing, low-rate extension in the Suez rift consistent with a continuing, though much-reduced, tectonic pull. The reported extension rate (≈0.5 mm/yr) is comparable to slow extension observed in parts of the western United States' Basin and Range province, where gradual crustal stretching creates alternating mountain ranges and valleys.
Implications
The study suggests that changing plate-boundary configurations do not necessarily shut off rifting entirely; instead, rifting forces can persist at low levels for millions of years. That persistence implies that regions labeled as "failed" rifts — including the Gulf of Suez — may still experience tectonic deformation and therefore could be more susceptible to earthquakes than previously assumed. The authors recommend revisiting other presumed "failed" rifts with modern measurement techniques.
"Changing plate boundary conditions don't necessarily shut down rifting," Fernández-Blanco added. "We may reveal that Earth's tectonic systems are more dynamic and persistent than we previously thought."
What this doesn't mean: The measured rate is very slow — about half a millimetre per year — so the Gulf of Suez is not rapidly opening into a new ocean. Instead, the study highlights persistent, low-rate tectonic activity that alters how geoscientists classify rift evolution and assess seismic risk.