In which part of the Earth does most volcanic activity occur?

Volcanic activity primarily occurs in the mantle, which is the layer of the Earth located beneath the crust and above the core. The mantle is composed of semi-solid rock that can flow over geological timescales. This movement is driven by convection currents caused by the heat from the core, leading to the melting of rocks and the formation of magma.

When this magma rises through the crust due to pressure and the dynamics of tectonic plate interactions, it can lead to volcanic eruptions. Most volcanoes are found at the boundaries of tectonic plates where the movement allows magma to escape to the surface. Thus, the mantle plays a crucial role in the processes that lead to the formation of volcanoes and the occurrence of eruptions, making it the part of the Earth where most volcanic activity takes place.