What is the Mohorovicic Discontinuity and how was it discovered?
The Mohorovicic Discontinuity is the boundary between the earth's crust and mantle. It was discovered by the refraction of seismic waves passing from one layer to the other.
While studying the earth quake waves after an earthquake in 1909 Andrija Mohorovicic noted that the earth quakes wave were refracted at a certain depth under the surface of the earth. This refraction is much like the change in direction observed when light waves move from the air into the surface of water.
Mohorovicic deduced from his observations that there was a sharp change in the structure of the earth at the point the earthquake waves were refracted. His deductions lead to the idea of the earth's interior being separated into the crust and the mantle.
The line where the crust and the mantle meet is called the Mohoroviviv Discontinuity named after Andrija Mohorovicic who discovered the change in the earth's structure.