When a seismic wave bounce backwards when it reaches a boundary?

When a seismic wave encounters a boundary between two different materials, part of the wave may be reflected back, which is known as reflection. This occurs because the wave's speed changes due to the differing properties of the materials, such as density and elasticity. The angle of incidence equals the angle of reflection, similar to light waves. This reflection can provide valuable information about the Earth's internal structure when analyzed by seismologists.