Earthquakes once considered “impossible” occur across the planet

The scientific community was never quite sure that “mantle earthquakes” were even real. Now, a new study has revealed a global map of this mysterious phenomenon.

After all, earthquakes that shake the Earth’s middle layer may be more widespread than scientists thought.

A new map of these mysterious deep earthquakes, revealed in a study earlier this month in Scienceshows that these Phenomena in the mantle occur all over the world and can have a variety of causes.

“This is interesting because mantle earthquakes were once considered impossibleor at least rare”, he told , leader of the study, Simon Klemperer.

These earthquakes originate below a boundary known as Mohorovičić discontinuity, or “Moho” — the line between the fragile crust and the hotter, more viscous mantle.

“We believe this firmly demonstrates that earthquakes exist below the Moho in many regions of the world,” said the Stanford University geophysicist.

As Live Science explains, most earthquakes start in the crust – “which is like a layer of toasted sugar on top of the softer, more deformable cream filling that is the mantle.” This fragile crust cannot deform, so it cracks under tension, causing the ground to shift and shake.

For a long time, geoscientists thought this couldn’t happen in the mantle, which has a texture similar to soft caramel and tends to flow rather than break down.

However, over the years, seismologists have found evidence of tremors with deep origin points more than 35 kilometers underground – which would place them below the Moho.

Accurately locating these earthquakes is, however, difficult, especially when they are not large. In general, these earthquakes are so deep that they cannot be felt at the surface, regardless of their magnitude.

In the new study, a method was developed that uses specific types of seismic shear waves that tend to get trapped in either the crust or the mantle, with the team focusing on the more elusive phenomenon of mantle earthquakes beneath continents.

Result: found mantle earthquakes all over the planet.

“There were some regions where no one had found these before, like in the Bering Sea,” he said. Vera Schulte-Pelkuma geologist at the University of Colorado Boulder who was not involved in the study, told Live Science.