What is a discontinuity in geology?
A discontinuity in geology is an area in the earth where the speed of earthquakes changes.
The best known discontinuity is the Mohorovicic Discontinuity which is know as the Moho for short. This is the division between the crust and the mantle. The Moho was discovered in 1909 by the seismologist Andrija Mohorovicic. He realized that the speed of seismic waves changed in this area and decided that this change must be because of the density of the material.