* Energy Builds Up: Earth's tectonic plates constantly move, but they don't always move smoothly. When they grind against each other, they create friction. This friction causes energy to build up in the rocks along the plate boundaries.
* Stress and Strain: The energy buildup creates stress within the rocks. Think of it like bending a piece of wood. As you bend it, the wood stores energy, and when you release it, the wood snaps back. Rocks, under pressure, can store this energy for a long time.
* The "Snap" - Fault Rupture: Eventually, the stress becomes too much for the rocks to withstand. They break along a fault line, releasing the stored energy in a sudden burst. This is called a fault rupture.
* Seismic Waves: The release of energy causes vibrations that travel through the Earth. These vibrations are what we call seismic waves. They are responsible for the shaking we feel during an earthquake.
There are two main types of seismic waves:
* P-waves (Primary Waves): These waves are the fastest and travel through solids, liquids, and gases. They compress and expand the rock as they pass.
* S-waves (Secondary Waves): These waves are slower and travel only through solids. They cause a shearing motion, moving the rock back and forth perpendicular to the wave's direction.
So, in summary, seismic waves occur when the energy built up in rocks due to tectonic plate movement is released suddenly during a fault rupture.
