Which type of fault is formed by horizontal shear stress?

A strike-slip fault is formed by horizontal shear stress, which occurs when two blocks of the Earth's crust slide past one another horizontally. This type of fault is characterized by the lateral movement of rock masses on either side of the fault plane. The tectonic forces responsible for shear stress typically arise from tectonic plate interactions, where one plate is sliding past another rather than moving closer or further apart.

In contrast, normal faults occur due to extensional forces that pull the crust apart, causing one block to drop down relative to another. Reverse faults result from compressional forces, where one block is pushed up over another block, typically on a steep angle. Thrust faults are a specific type of reverse fault with a low-angle fault plane. Therefore, strike-slip faults distinctly represent horizontal shear stress, as indicated by their mechanism of movement along the fault line, making them the correct answer.