Question

Which one among the following factors contributes the least amount of heat to the Earth's annual heat budget?

• A. Geothermal flux from Earth's interior
• B. Reflection and re-radiation of Solar energy
• C. Energy released from Earthquakes
• D. Rotational deceleration by Tidal friction

Hint:

Remember: Earth's heat budget is overwhelmingly solar-driven. Minor contributors include geothermal flux and tidal friction. Earthquake energy, although spectacular locally, is negligible on a global annual scale.

Answer 1

The Correct Option is C

Step 1: Major contributors to Earth's heat budget.
The Earth's heat budget is dominated by solar radiation. The incoming solar radiation, its reflection, absorption, and re-radiation constitute the largest share of energy exchange. Step 2: Secondary contributors.
Other minor contributions come from geothermal flux (heat flow from Earth's interior due to radioactive decay and residual formation heat) and tidal friction (causing small dissipation of rotational energy as heat). Step 3: Earthquake energy release.
The global annual energy released by all earthquakes combined is negligible compared to geothermal heat or tidal dissipation. While individual large earthquakes release tremendous localized energy, the total annual contribution is extremely small relative to Earth's overall energy budget. Step 4: Comparison.
- Solar radiation (via reflection/re-radiation): Dominant component.
- Geothermal flux: Small, but continuous and measurable (~0.1 W/m$^2$ globally).
- Tidal friction: Even smaller, but still continuous.
- Earthquake energy release: Intermittent and minuscule compared to the above. \[ \therefore \ \text{The least contributor to the Earth's annual heat budget is energy released from earthquakes.} \] \[ \boxed{\text{Energy released from Earthquakes}} \]