Seismic waves originate during an earthquake occurring on the earth’s surface. One of the layer from the internal layers of the Earth, determined on the basis of these seismic waves, is substratum.
Characteristics of substratum are:
1. It is the intermediate layer of earth based on the classification of seismic waves.
2. This layer reaches down to the depth of 2900 km below the crust.
3. The upper part of the substratum is called Astheno sphere.
4. This layer is the main source of lava released during volcanic eruption.
5. A substratum is formed from concrete rock.
6. Due to the heat, pressure and density in this layer, the concrete rock is believed to have a change in the state of matter.
