SOURCES OF INFORMATION ABOUT THE INTERIOR. [ PART 2]: UPSC Daily Important Topic | 25 April 2022
INDIRECT SOURCES.
□ Seismic waves
◇ They are the most important source available to understand the layered structure of the earth.
◇ The velocity of seismic waves changes as they travel through materials with different elasticity and density.
□ Meteorites
◇ Meteorites and Earth are born from the same nebular cloud. Thus, they are likely to have a similar internal structure.
□ Gravitation
◇ The gravitation force (g) is not the same at different latitudes on the surface. It is greater near the poles and less at the equator.
◇ This is because of the distance from the centre at the equator being greater than that at the poles.
◇ The gravity values also differ according to the mass of material.
□ Magnetic field
◇ The geodynamo effect helps scientists understand what’s happening inside the Earth’s core.
◇ Shifts in the magnetic field also provide clues to the inaccessible iron core.