Cours 3: Gravimétrie
Cours 3: Gravimétrie
Cours 3: Gravimétrie
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Résumé<br />
● Before we can start interpreting gravity gravity anomalies we need to make sure we’re comparing apples to apples…<br />
● FreeAir correction<br />
■ Assume there’s nothing but vacuum<br />
between observer and reference ellipsoid<br />
■ Just a distance correction<br />
Δg<br />
Δg<br />
FA<br />
FA<br />
δg<br />
δ ⎛ GM ⎞<br />
= Δr<br />
= ⎜ h 2 ⎟<br />
δr<br />
δr<br />
⎝ r ⎠<br />
2gh<br />
= −<br />
r<br />
● Bouguer correction<br />
■ Assume there’s a constant density plate between observer and reference ellipsoid<br />
■<br />
■<br />
Remove the gravitation attraction due to the mass of the plate<br />
If you do a Bouguer correction you must follow up with a freeair correction Δg<br />
B = 2π<br />
Gρh
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