Why secondary waves do not travel through outer core?

 Secondary waves are the seismic waves which are produced during the earthquake.

Secondary waves are the body waves as they vibrate perpendicular to the direction of wave propagation.

These waves generally posses short wavelength and high frequency due to which it is responsible for shaking of the surface during earthquake.

A part from this, secondary waves can only travel in solid medium unlike primary waves.

As liquid and gas lacks rigidity or resistance to change in form.

 Due to which secondary waves are not propagated through liquid and gaseous medium as they are also called as shear waves.

To know about the detail structure and distribution of materials inside the earth, seismic waves are also produced artificially.

But unlike other body wave, secondary wave cannot penetrate the surface of outer core.

Due to the inability of the wave to penetrate the outer core, no exact information of the core is exactly provided.

But most importantly, it proves that the outer layer of the core is in liquid state as secondary waves cannot pass through liquid.

The thickness of the outer core is assumed to be 2900km – 4982km as it is separated from lower mantle by Gutenberg- Weichert discontinuity.