The type of seismic wave that does not pass through fluid is the S-wave (secondary wave).

Here's why:

* S-waves are shear waves, meaning they cause particles to move perpendicular to the direction of wave propagation. This motion requires a rigid medium like solid rock to transmit.

* Fluids (like water or molten rock) cannot support shear forces, so S-waves cannot travel through them.

In contrast, P-waves (primary waves), which are compressional waves, can travel through both solids and fluids. They cause particles to move back and forth in the same direction as the wave travels.