Daily News Analysis ‘Interior Structure of the Earth and Core Dynamics ’ : 25 May

Why in News:

• Geomagnetic data mapping has revealed a dramatic, rapid directional shift of liquid iron currents flowing within Earth’s molten outer core beneath the equatorial Pacific Ocean.

Earth’s Interior Core Facts:

• Concentric Stratification: Earth’s interior is chemically and physically divided into three distinct concentric layers: the outer Crust, the solid-state Mantle, and the high-density Core.
• The Crust Baseline: The outermost solid layer, varying from a thin oceanic crust (roughly 5 km thick, composed of dense basaltic Sima—Silica and Magnesium) to a thick continental crust (up to 70 km under mountains, composed of granitic Sial—Silica and Aluminium).
• The Mantle and Asthenosphere: Extending down to 2,900 km, the mantle comprises 83% of Earth’s volume; its upper section houses the Asthenosphere, a highly viscous, mechanically weak, semi-fluid zone that feeds volcanic magma and drives tectonic plate movements.
• The Core Boundary: The boundary separating the lower mantle from the core is known as the Gutenberg Discontinuity, located at a depth of roughly 2,900 km.
• Liquid Outer Core: A massive, churning liquid layer extending from 2,900 km to about 5,150 km beneath the surface, composed primarily of molten iron and nickel (known collectively as the Nife layer).
• The Geodynamo Mechanism: Convection currents of molten iron inside the liquid outer core generate electric currents which, combined with Earth’s rotation, act as a massive generator creating the planetary magnetic field that shields Earth from harmful solar radiation.
• Solid Inner Core: The innermost sphere extending from 5,150 km to the Earth’s center at 6,371 km; despite extreme temperatures exceeding 5,000 °C, intense gravitational pressure forces the iron and nickel to remain strictly in a solid state.
• Magnetic Field Jerks: Recent satellite mapping demonstrates that outer core fluids can rapidly shift direction, which explains historical westward magnetic drifts, a 10% structural flow imbalance between the hemispheres, and sudden spikes or “jerks” in magnetic readings.