What is 3D seismic tomography?

3D seismic tomography is like taking X-rays of the Earth to see what’s inside it.

Imagine you have a big, squishy toy ball, like one of those stress balls you squeeze when you're upset. You can’t see what's inside without breaking it open. But if you shake it and watch how it moves from different angles, you could guess what's inside, maybe there are little rocks or soft spots. That’s kind of how 3D seismic tomography works.

When scientists want to know what's deep inside the Earth, they send out sound waves, like ripples in a pond, through the ground. These sound waves travel at different speeds depending on what they pass through. If they go through something hot or soft, they might slow down; if they go through something cold or hard, they might speed up.

By listening to how these sound waves come back from all around the Earth, scientists can make a picture, like a 3D map, of what’s happening deep underground. It's like using echoes to figure out what’s hiding inside a big, squishy ball.