Gravity Field Separation

Gravity Field= Regional + Residual

Regional Field comes from deep seated structures like Moho

Residual field comes from shallow (near surface) structures

Example

Observed gravity (Bouguer) map

Using graphical separation method

Regional field

Residual field

Observe the differences

Regional fields are generally smoother than residual> Residual anomalies are usually higher in amplitude

Separation Methods

Graphical method: Depends on removing the trend

( regional) from Bouguer anomalies. Griffin Method Applying averaging scheme to gravity

maps through averaging the gravity values around a point then subtracting from the gravity value at the point to get the residuals.

Another example

Bouguer

Regional

Residual

Possible Interpretation