The type of seismic waves that can travel through solids but not liquids are S-waves (secondary waves).

Here's why:

* S-waves are shear waves, meaning they cause particles in the medium to move perpendicular to the direction of wave propagation. This motion requires a rigid structure like that found in solids.

* Liquids and gases do not have the rigidity to support shear waves. Instead, the particles in liquids and gases move back and forth in the same direction as the wave propagation, which is characteristic of P-waves (primary waves).

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