Which type of seismic waves are the L waves?

• A. Surface waves, specifically R waves
• B. Body waves, specifically P waves
• C. Body waves, specifically S waves
• D. Surface waves, specifically L waves

Answer: (D)

L waves are Love waves, a type of surface wave that travels along the Earth's exterior. They arise when seismic energy is guided by near-surface layer contrasts and move with horizontal shear motion, perpendicular to the direction of travel, while showing little vertical displacement. This surface-bound motion means they typically arrive after the faster body waves (P and S) and can cause strong, damaging shaking at the surface. They are distinct from Rayleigh waves, which involve elliptical ground motion, and from body waves (P and S) that travel through the interior.