The North American Continent is Dripping Into the Mantle Beneath It

The continent, especially beneath the Midwest is falling

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Thanks in large part to technological advancements, scientists are making incredible discoveries in practically every field. Many of these revelations teach us more about our planet, not just about life inhabiting it and its terrain, but also what Earth is like beneath our feet.

Many of us learned the basics in school, that Earth has many layers and is billions of years old. However, scientists have learned some new and incredible things about Earth’s interior over the last few years. For instance, in March 2025, scientists discovered that the American Midwest is “dripping” into the mantle from its underside.

Quick Geology Lesson

Everything we know about Earth’s interior comes from special sensors called seismographs that detect earthquake vibrations across the planet. Vibrations travel at different speeds as they pass through objects, so scientists can use seismographs to measure these speeds and determine the densities of materials the vibrations pass through.

This has allowed scientists to identify Earth’s various layers, including the four more well-known ones — inner core, outer core, mantle, and crust — along with lesser-known and more recently discovered layers such as Earth’s inner-inner core, and one with mountains and oceans.

Now, seismologists are using an advanced technology called full-waveform inversion, which utilizes computer models to combine the seismic readings from Earth’s interior to create a single, clear image.

Scientists are using this new technology to learn more about the insides of our planet and have already discovered some surprising things, like mysterious landmass “anomalies” that “shouldn’t be there,” and two mysterious ginormous blobs, or that parts of the bottom side of Earth’s crust occasionally break off and sink into the mantle below.

And it’s the latter that we’ll discuss today.

Cratonic Thinning

You’re likely already familiar with Earth’s plate tectonics. The planet’s outermost layer, also known as the lithosphere, is made of Earth’s crust and upper mantle, which is broken up into large rocky plates that move, resulting in earthquakes.

However, while the borders of these plates are known to collide, their interiors remain untouched, and these regions of tectonic plates are called cratons.

Cartons are the oldest parts of the Earth’s crust and, being located in the middle of tectonic plates, they’ve mostly remained intact for billions of years without experiencing significant tectonic activity for a very long time.

Yet, despite their resilience, cratons can experience changes known as cratonic thinning, which chips away at the underlying rock layer, thus weakening it.

Thankfully, cratonic thinning involves time scales running millions to billions of years. Scientists have only ever seen the results of cratonic thinning, but the changes have never been observed in action by scientists — until now.

New Research