Reference gravity, elevation and Bouguer corrections
A gravity anomaly is an observed/modelled field difference relative to a stated reference and correction convention.
Key knowledge
A gravity anomaly is an observed/modelled field difference relative to a stated reference and correction convention. In the spherical reference g(h)=GM/(R+h)²≈g₀(1−2h/R); reducing an elevated observation to the reference level adds 2g₀h/R at first order. A flat infinite slab of density contrastΔρ and thicknessH contributes downward acceleration 2πGΔρH on its exterior side. Removing a positive slab contribution is a distinct Bouguer correction.
Values and equations
g(h)=GM/(R+h)²≈g₀(1−2h/R); Δg_slab=2πGΔρH
- g,g₀,Δg_slab
- gravity magnitudes and downward slab anomaly m s⁻²
- G
- Newtonian gravitational constant m³ kg⁻¹ s⁻²
- M
- reference spherical mass kg
- R,h,H
- reference radius, elevation and slab thickness m
- Δρ
- density contrast to the reference body kg m⁻³
Conditions and scope
- |h|≪R for the linear elevation approximation; reference g₀=GM/R². Slab formula assumes an infinite planar uniform density contrast and observations on one exterior side; positive contrast lies below the observer for the stated downward sign.
- Actual normal gravity includes rotation/shape/latitude, and terrain, tides, instrument drift and height/datum uncertainty need treatment. A gravity anomaly is not automatically a unique rock-density map. 1mGal=10⁻⁵m s⁻²; correction signs depend on the documented convention.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Read actual printed55–56 exterior spherical potential, reference-oblate/elevation discussion, and printed58 sheet limit. Linearized the spherical inverse-square field explicitly; distinguished measurement reduction from mass-attraction removal. Excluded datedG/numeric normal-gravity coefficients, source sign-of-latitude typo and a spherical model claimed exact for rotating Earth.
2026-10-10 · Independent AI editorial review: All73 exact supplement compact statements, conditions, displayed equations and247 origin semantic links read; all109 combined original36+supplement73 author-source rows, exact locators, hypotheses, exclusions and disclosed derivations assessed. Original36 exact scientific content is independently approved in the linked receipt. All18 inherited Earth compact references and shared Math/Physics/Measurement methods were considered in the full practical Earth inventory. Targeted actual primary sections listed below; not every source body/proof or every possible university elective independently reread. AI editorial reference review, not human certification, full-degree proficiency, new experimental validation or a claim of whole combined Earth-and-Cosmos approval. Receipt: earth-completion-independent-content-inventory-review.1.
Entry details
Permanent link to this entry ↗- Record identity
- uni-earth-gravity-reference-corrections
- Revision
- core.1
- Structured reference record
- University core expansion