Question

why temperature increases as we go down(underground)?

Answer 1

The process of the increase of the temperature as one moves more towards the center of the earth, that is, towards the underground, is known as the Geothermal Gradient.

Due to the decay of naturally radioactive substances, or even due to the heat made by the movement of the tectonic plates, and formation of gravitational acceleration, the temperature increases.

Answer 2

Explanation:

it is due to lapsrate with every 32 km of descent the temperature increases