Overview:
Scientists are uncovering global evidence of mantle earthquakes once thought impossible, revealing new insights into how stress and deformation operate deep inside Earth.
For decades, conventional wisdom among geologists held that significant earthquakes could only occur in Earth’s brittle crust, where rock fractures in response to tectonic stress. Beneath that, in the mantle, heat and pressure were thought to prevent rock from breaking — instead causing it to flow. But a wave of recent research is overturning that assumption. Scientists now say that earthquakes do occur in the mantle, and not just rarely or locally — they have now been identified in multiple regions around the globe, revealing mantle earthquakes once thought impossible.
This emerging picture comes from a suite of studies that together show how mantle quakes — long thought “impossible” except in subduction zones — are more common and widespread than once believed. These findings suggest that mantle earthquakes, once thought impossible, are not geological anomalies but a recurring feature of Earth’s interior.
New Global Map Shows Widespread Mantle Seismicity
In a first-of-its-kind global catalogue, Stanford researchers analyzed seismic data from more than 46,000 earthquakes recorded since 1990, identifying 459 that originated deep in the mantle beneath continental regions. The findings, reported by Stanford researchers in peer-reviewed research, reveal regional clustering beneath the Himalayas and near the Arctic’s Bering Strait.
“We haven’t had a clear global perspective on how many continental mantle earthquakes are really happening and where,” said lead author Shiqi (Axel) Wang of Stanford University. “With this new dataset, we can start to probe into the various ways these rare mantle earthquakes initiate.”
These quakes occur below the Mohorovičić discontinuity, or Moho, long thought too hot and pressurized for brittle fracture. New evidence shows such earthquakes do occur within continental interiors, challenging long-held assumptions about Earth’s mantle.
Local Studies Add Depth to the Global Picture
While the global map gives a broad view, other research zooms in on specific mantle earthquake cases.
A peer-reviewed study examined the Wyoming Craton — a stable interior region of the North American continent — and identified several rare upper-mantle earthquakes beneath Wyoming and Utah between 1979 and 2023. Though the total number of events was small, it was shown that these earthquakes occur at depths well below the boundary between the crust and mantle, in regions where mantle material is typically ductile under normal conditions. The authors concluded that these events, although rare, are scientifically valid and offer additional information on the localization of stress, even in areas that were not thought to be capable of it.
Such studies may also provide insight into the mechanism by which earthquakes in the mantle are possible, perhaps in regions where the temperature, composition, and thickness of the lithosphere are favorable for a brittle failure.
Recent discussion of the 2025 Kamchatka subduction-zone earthquake has highlighted the complexity of large megathrust events and their regional geological impacts. (Related reading: VolcanoCafe analysis of the Kamchatka earthquake)
Mechanisms: More Than One Pathway to a Mantle Quake
Recent studies in the Mid-Atlantic Ridge region provide further insight into the problem. Data show earthquakes occurring near the crust–mantle boundary and in the uppermost mantle, likely linked to CO₂ degassing from rising mantle melts.
In this study, which is available for free at PubMed Central, researchers found that gas exsolution from rising mantle melts could trigger small earthquakes in the upper mantle and lowermost lithosphere due to changes in stress conditions. This mechanism may trigger mantle earthquakes in volcanic or upwelling regions, pointing to multiple deep-quake triggers. Though too small to cause damage, deep quakes act as natural probes of Earth’s interior.
Why This Matters to Earth Science — and to the Public
On their face, mantle earthquakes don’t pose a direct hazard in the way shallow crustal quakes do. Because they originate deep below the surface, they generally produce minimal shaking at the surface. But their scientific importance is real.
For one, they challenge long-held assumptions about rocks deep inside the planet. The conventional model held that mantle rock simply doesn’t break — it creeps or flows. Under the right conditions, deep rock can fracture and generate globally detectable seismic waves.
In addition, these earthquakes give a rare glimpse into the behavior of the inner Earth. From the waveform and depth information, researchers can infer temperature, pressure, and composition beneath the continents. This could lead to better models of tectonics, convection in the mantle, and shallow earthquake dynamics.
According to a EurekAlert! summary of the Stanford-led research, continental mantle earthquakes may be part of an interconnected earthquake cycle involving both the crust and upper mantle.
That means mantle quakes may not be isolated oddities but integrated parts of how our planet’s tectonic engine works.
Mantle earthquakes, once thought impossible, are now revealing how stress and deformation operate deep within the planet.
A Shift in How Scientists Understand Earth’s Interior
Evidence of earthquakes in the mantle is leading to a reevaluation of stress models on Earth. Stress build-up was considered to happen largely in the brittle crust. Evidence of failure of mantle rocks indicates that tectonic stresses extend deeper than previously believed.
“Photo by [RDNE Stock project] on Pexels”
This result could explain mysterious seismic events in stable continental areas with no surface faults. Mantle earthquakes could indicate tectonic loading far beneath the Earth’s surface. Researchers emphasize that this does not mean a greater risk of earthquakes, but much is still not known about the Earth’s interior. As seismic data improve, mantle earthquakes are expected to sharpen models of plate tectonics, continental evolution, and deep Earth structure.
Looking Forward: Mapping More of the Invisible Earth
One thing is clear: the picture of Earth’s interior is far richer and more complex than once imagined. Improved seismic networks and tools are revealing features once thought undetectable.
Scientists expect many more mantle earthquakes to be identified and better understood. That could lead to refined seismic hazard models and a deeper understanding of planetary stress.
The once-dismissed idea that the mantle can host earthquakes is now widely accepted. Instead, it’s becoming one of the most surprising frontiers in Earth research.
Sources:
EurekAlert! — “Study reveals the extent of rare earthquakes in deep layer below Earth’s crust”
Nature Communications — “Deep mantle earthquakes linked to CO₂ degassing at the Mid-Atlantic Ridge”
Geophysical Research Letters — “Upper Mantle Earthquakes Along the Edge of the Wyoming Craton”
VolcanoCafe — “The Kamchatka earthquake”
Editor’s Disclaimer: This article is intended for informational and educational purposes only. It summarizes findings from peer-reviewed scientific studies and reputable research institutions and does not constitute professional, geological, or safety advice. While the research discussed explores earthquakes occurring deep within Earth’s mantle, scientists emphasize that such events generally pose no direct risk to the public. Readers are encouraged to consult original research publications and qualified experts for detailed interpretation of scientific data.
More from Presence News:
