Here's how it works:
* Seismometers are sensitive instruments that detect and record ground motion, including the vibrations caused by earthquakes.
* Earthquake waves travel through the Earth's interior in different ways, depending on the material they encounter.
* P-waves (primary waves) are compressional waves that travel faster and can pass through solids, liquids, and gases.
* S-waves (secondary waves) are shear waves that travel slower and can only pass through solids.
* By analyzing the speed, direction, and arrival times of these waves, scientists can deduce the composition and structure of Earth's interior.
Think of it like an ultrasound for Earth!
