Scientists are discovering that deep earthquakes, which occur below the Earth’s surface, are more common than they first thought. A new study led by geophysicist Simon Klemperer at Stanford University reveals that these quakes happen worldwide and may result from various geological activities.
For years, the scientific community believed that earthquakes could only happen in the Earth’s crust—our outer shell. This layer is like a crispy layer on a dessert, cracking under stress. Below it lies the mantle, a thicker layer that’s often too soft to break in the same way. However, recent findings show that quakes can indeed occur in the mantle at depths over 22 miles (35 kilometers), beneath the so-called Mohorovičić discontinuity, or “Moho.”
Identifying these deep quakes has always been challenging. Most of them are not strong enough to be felt on the surface, and their subtle signals can be mixed with shallower quakes. Klemperer and graduate student Shiqi Wang developed a new method to pinpoint whether an earthquake starts in the crust or the mantle. They focus on specific seismic waves that behave differently in these two layers.
In a significant study published in Science, they expanded this method beyond prior research conducted in Tibet and mapped mantle earthquakes across the globe, excluding subduction zones where deep quakes are well understood. Their findings revealed previously unknown clusters of deep earthquakes stretching from the Alps to the Himalayas and even in the Bering Sea—a surprising discovery!
Why does this matter? Geologists like Vera Schulte-Pelkum from the University of Colorado Boulder believe this global map can drive future research into mantle quakes. Understanding these events could shed light on how they affect geological structures, including mountain ranges and rift valleys in places like East Africa.
Statistics show increasing interest in this field. Searches for “deep earthquakes” have surged on platforms like Twitter, with many users expressing curiosity about how these phenomena might reshape our understanding of the Earth. Experts predict that as technology advances, monitoring and understanding these deep seismic events will only improve.
This new research enriches our knowledge of Earth’s inner workings. Klemperer expressed excitement about having a tool that can be widely applied to study these intriguing mantle quakes. The deeper understanding could not only answer scientific questions but also contribute to better predicting seismic activities that might impact communities worldwide.
