P-waves, or primary waves, are a type of seismic wave generated by earthquakes. They are the fastest seismic waves, traveling through solid, liquid, and gas. P-waves compress and expand the material they move through, similar to how sound waves travel through air. When an earthquake occurs, P-waves are the first to be detected by seismographs, making them crucial for understanding the event's location and magnitude. Their speed allows them to provide early warnings, giving people a few seconds to prepare before the more damaging S-waves arrive.