2. Sources of Information
Most of the information about the Earth’s interior is based on inferences drawn from different
sources – both direct and indirect.
2.1. Direct Sources2.2. Indirect Sources2.2.1. TemperatureFig 1: Temperature profile of the inner Earth2.2.2. Density2.2.3. Pressure2.2.4. Gravitation force2.2.5. Magnetic surveys2.2.6. Meteorites2.2.7. The Moon2.2.8. Evidence from Theories2.2.9. Earthquake WavesFig 2: Particle motion in seismic waves Fig 3: Arrival time of seismic wavesFig4: Shadow Zones Fig 5: EarthquakeFig 63.2. The MantleFig 7: Earth Crust3.3. The CoreFig 8: The DiscontinuitiesTable 3.1