Structural Changes in Earth's Inner Core

Geography

A Nature Geoscience study reveals structural shifts in Earth’s inner core.

Methodology: Seismic waves from 1991-2024 near Antarctica show subtle changes, indicating core dynamics.
Structural Changes: The near surface of Earth's inner core is undergoing structural changes, challenging the earlier belief that it is rigid and stable
Cause: Viscous deformation due to interactions between the molten outer core and solid inner core, similar to magma flow.

Structure: A solid iron-nickel ball under extreme pressure.
Depth & Size: 5,150 km deep, 1,220 km radius; separated from the outer core by the Lehmann Discontinuity.
Magnetism: Influences Earth’s magnetic field, while the outer core’s swirling iron generates it.
Rotation: Moves slightly faster than Earth, completing one extra rotation every 1,000 years.
Growth: Expands 1 mm/year, unevenly, and will never fully solidify due to slow crystallization and radioactive decay.

Earth’s Interior

Earth's interior consists of concentric layers:

Crust (Outer Layer):
- Continental Crust: ~35 km thick, made of silica (Si) & alumina (Al) ("sial").
- Oceanic Crust: ~5 km thick, composed of silica (Si) & magnesium (Mg) ("sima").
Mantle (Thickest Layer):
- Extends up to 2,900 km, rich in iron & magnesium silicates.
- Contains the asthenosphere, a semi-molten layer driving plate movement.
Core (Innermost Layer):
- Radius: ~3,500 km, composed of nickel (Ni) & iron (Fe) ("nife").
- Outer Core: Liquid generates Earth’s magnetic field.
- Inner Core: Solid due to immense pressure.