The interior parts of the Earth are invisible and unreachable. Man has seen the interior part to some extent in direct form through mining and intrusive actions. Due to the rapid increase in temperature with depth, it is not possible to do more deep mining and exploration. There is so much heat under the surface that any kind of instrument used in mining can melt.
Therefore, the mining work is limited to a lesser depth. Volcanic eruptions are the main source of direct information about earth’s internal structure through the emitted lava and gases. There are many anomalies in the interior of the Earth that make it unique.