Final answer:
The question related to P-waves and S-waves, produced by earthquakes. P-waves can travel through both solids and liquids and provide information about the internal structure of Earth. S-waves cannot travel through liquids and therefore create 'shadow regions' they can't reach.
Step-by-step explanation:
The deliberation in the question pertains to the propagation of P-waves and S-waves, generally known as seismic waves, within the planet. These waves are produced by earthquakes and they travel through the Earth in distinct manners.
P-waves, or pressure waves, are longitudinal waves that can travel through both solid and liquid materials, including Earth's core. As a result, these waves provide valuable information about the internal structure of the Earth.
S-waves, or shear waves, are transverse waves and cannot pass through liquids, including Earth's liquid core. Consequently, there are certain 'shadow regions' on Earth's surface that these waves cannot reach, but which are reached by P-waves.
By analyzing the arrival times and locations of these two types of waves after an earthquake, seismologists can infer much about the structure and composition of Earth's interior layers.
Learn more about Seismic Waves