Moho (Mohorovičić Discontinuity)

The Moho, or Mohorovičić Discontinuity, is a boundary within the Earth that separates the crust from the underlying mantle. Discovered in 1909, it is characterized by a sudden increase in seismic wave speeds, indicating a change in rock composition. The crust is made of lighter rocks, like those on Earth's surface, while the mantle beneath consists of denser, ultra-mafic rocks. The Moho's depth varies under continents and oceans, averaging about 35 km beneath continents and 7 km beneath ocean floors. This boundary is crucial for understanding Earth's internal structure and how tectonic plates move.