Snippets of Science

In 2025, researchers from the University of Utah were able to identify a class of earthquakes beneath the Earth’s crust that had not been seen in these conditions before, called “continental mantle earthquakes.” The authors of the study believe that this can give us some additional insight as to what the Earth looks and acts like beneath the surface.

Earthquakes are usually caused when two tectonic plates interact with each other and occur in the part of the Earth known as the crust, the thin layer of solid rock that sits above the mantle. They press against each other until they move past each other when, like a spring that was being bent, they release their energy into the surrounding rock and cause an earthquake.

These continental mantle earthquakes act differently, with one identified in 2025 shortly after this paper was released being detected over 20 km below the crust, firmly in the mantle. Because the mantle is so much hotter than the crust, it is much softer and should be unable to press against itself in the ways needed to generate earthquakes.

Much like the surface of the Earth, not everything inside of it is made of the same materials. In a University of Utah press release, lead author of the paper identifying this earthquake Dr. Keith Koper compared the type of mantle beneath Utah, Wyoming, and Idaho to an iceberg, an area of more solid rock surrounded by softer rock that can flow more easily. This particular structure has been named the Wyoming Craton. Continuing, they said, “We think it’s that interaction between the keel of the iceberg and the medium around it that’s leading to these earthquakes.”

Though several of the earthquakes were identified in the state of Wyoming, they don’t appear to be related to the legendary Yellowstone supervolcano, a subject that has gained notoriety in recent years as fears of its eruption continue to grow in the public consciousness. Dr. Koper clarified in an email to me that these earthquakes are far too weak to have any significance to the structure beneath Yellowstone.

In the same email, Dr. Koper offered an extra fact that was too interesting for me to leave out. There is actually a relation between the craton causing these earthquakes and Yellowstone, but it’s acting in the other direction. Underneath Yellowstone is a mantle plume, making it geologically active with geysers and hot springs and the supervolcano. This mantle plume is slowly eroding the Wyoming Craton, causing it to change shape over time.

Understanding the causes of these strange deep earthquakes allows us to better understand what the ground beneath us is made of. Hopefully, these discoveries can give us more data to help with our ability to predict major disruptions to the Earth’s surface, from volcanoes to earthquakes to, perhaps, the far future of what our planet will look like.

Featured Image by “The Utahraptor” through Wikimedia Commons