■ SURFACE WAVES ( L-WAVES)
Topic — Interior of Earth
✓ The body waves interact with the surface rocks and generate new set of waves called surface waves (long or L-waves). These waves move only along the surface.
✓ Surface Waves are also called long period waves because of their long wavelength.
✓They are low-frequency transverse waves (shear waves).
✓They develop in the immediate neighbourhood of the epicentre and affect only the surface of the earth and die out at smaller depth.
✓They lose energy more slowly with distance than the body waves because they travel only across the surface unlike the body waves which travel in all directions.
✓ Particle motion of surface waves (amplitude) is larger than that of body waves, so surface waves are the most destructive among the earthquake waves.
✓ They are slowest among the
earthquake waves and are recorded last on the seismograph.
