Final answer:
Seismic waves that travel only near Earth's surface are of two main types: a. P-wave and S-wave. P-waves are longitudinal or pressure waves, while S-waves are transverse or shear waves.
Step-by-step explanation:
Seismic waves that travel only near Earth's surface are of two main types: a. P-wave and S-wave. P-waves are longitudinal or pressure waves, while S-waves are transverse or shear waves. These waves propagate at different speeds and have distinct characteristics.
P-waves are faster and arrive at a seismograph first, while S-waves follow and arrive slightly later.