LISBON, Portugal, July 16 — A magnitude 5 earthquake struck the southern Mid-Atlantic Ridge at 21:16 UTC today, the U.S. Geological Survey reported, rattling one of the planet’s most seismically restless underwater mountain ranges.
The quake hit at a depth of 10 kilometers. That makes it a shallow event, and here’s what that means in plain terms: think of it like dropping a rock into a pond from just above the surface versus throwing it from a high cliff. Shallow quakes — anything less than 70 kilometers deep — tend to transfer more of their energy straight up to the seafloor, producing stronger shaking than a deeper earthquake of the same magnitude would.
No tsunami warning was issued following the event, the USGS confirmed.
What a magnitude 5 earthquake feels like
Earthquakes in the magnitude 5 range are classified as moderate. They can cause minor to moderate damage near the epicenter — items falling off shelves, cracks in plaster, that sort of thing — but because this one struck along the Mid-Atlantic Ridge, far from populated landmasses, the practical upshot for most people is minimal. The shaking was felt primarily by research vessels, passing ships, and the seafloor itself.
The Mid-Atlantic Ridge is a divergent tectonic plate boundary where the North American and Eurasian plates, and the South American and African plates, are slowly pulling apart. Magma rises from the mantle to fill the gap, creating new oceanic crust. That constant geologic stretching and cracking makes the ridge one of the most earthquake-prone places on Earth.
A history of shaking in the neighborhood
The USGS records show that at least 58 earthquakes of magnitude 5.0 or greater have occurred within roughly 300 kilometers of today’s epicenter over the past two decades. The largest of those was a magnitude 6.1 event in 2017. That’s a reminder that while magnitude 5 quakes are common here, the region can produce more energetic shaking.
Seismologists note that aftershocks are common following an earthquake of this size. They may continue for days or even weeks. People in the affected area — which in this case means crew on any ships or research platforms in the vicinity — are generally advised to be prepared for further shaking. The USGS detected the event through its real-time global seismic monitoring network, a system of seismometers spread across the planet that allows scientists to locate and measure earthquakes within minutes.
The southern Mid-Atlantic Ridge sits far from major cities, so damage and injury reports are unlikely. But the event is a useful reminder, in concrete terms, that the Earth’s tectonic machinery is always running — even when nobody’s around to feel it.
Sources
- Strong 5.0 Earthquake Rocks Southern Mid Atlantic Ridge; No…
- Three Moderate Quakes Rock Northern Mid Atlantic Ridge; No…
