Testhullámok

Testhullámok, often translated as body waves, are seismic waves that travel through the Earth's interior. They are generated by earthquakes and other seismic sources. Unlike surface waves, which travel along the Earth's surface, body waves can penetrate the planet's inner layers. There are two main types of body waves: P-waves and S-waves.

P-waves, or primary waves, are compressional waves. They travel faster than S-waves and can propagate through solids, liquids, and gases. As a P-wave passes, particles in the Earth move back and forth in the same direction as the wave is traveling, causing compression and expansion of the material.

S-waves, or secondary waves, are shear waves. They travel slower than P-waves and can only propagate through solids. In an S-wave, particles move perpendicular to the direction of wave propagation, causing a shearing motion. This property is why S-waves cannot travel through the Earth's liquid outer core.

The different speeds and behaviors of P-waves and S-waves allow seismologists to study the Earth's internal structure. By analyzing the arrival times of these waves at different seismic stations, scientists can determine the location of earthquakes and infer the composition and physical state of the Earth's mantle and core. The inability of S-waves to pass through the outer core, for example, provided crucial evidence for its liquid nature.