Trigger an earthquake and observe P-waves, S-waves, and seismograph readings.
P-waves (Primary) are fastest, compressional, travel through solids & liquids. S-waves (Secondary) are slower, transverse, only through solids. Surface waves cause the most damage with rolling/swaying motion. The Richter scale is logarithmic — each whole number = 10× more ground motion and 31.6× more energy. Seismographs record all three wave types, with P-waves arriving first.