A shear wave (S wave) is a type of seismic body wave that shakes the ground back and forth perpendicular to the direction the wave is moving.
Answer: Option A
Step-by-step explanation:
Shear waves move through the body of an object, without following surface waves. These are called Secondary waves and S-waves. These are transverse too. Shear, as the name suggests, denotes a wave which is abnormal, i.e. perpendicular to the normal waves.
These normal waves are those which travel through the surface of the body. Unlike them, the S-waves travel move through the body, hence causes vibrations. These uncertain vibrations cause a body to shake, and therefore, the ground is shaken on the onset of shear waves. These are the causes of earth quakes.