LAYERS OF THE EARTH ACCORDING TO PHYSICAL PROPERTIES

MESOSPHERE

The strength of a solid is controlled by both temperature and pressure. When a solid is heated, it loses strength. When it is compressed, it gains strength. Differences in temperature and pressure divide the mantle and crust into three strength regions. In the lower part of the mantle, the rock is so highly compressed that it has considerable strength even though the temperature is very high. Thus, a solid region of high temperature but also relatively high strength exists within the mantle from the core-mantle boundary to a depth of about 350 km and is called the Mesosphere, also called the middle sphere.