Bouguer anomaly

The Bouguerplatte is a model of gravimetry to obtain the Bouguer anomaly. The gravity measurements are corrected to a reference level to allow comparability of different measurements. The Bouguerplatte is an infinitely extended plate of thickness h between the measurement points and the reference level. The gravitational acceleration is perpendicular to this plate, and the density is homogeneous.

The simple Bouguerplatte can be selected flat or spherical depending on the model and neglected influences the topology. The complete Bouguerplatte refers influences the topology with a.

Basics of Bouguerplatte

The mathematical basis of the Bouguerplatte is the vertical component of the gravitational acceleration. This is applied to an infinitely extended layer of thickness h and we obtain:

In this formula, g is the gravitational constant, and the average density of the stone plate. Usually have a density of adopted. One thus gets an average correction of the Bouguerplatte.

Application of Bouguerplatte

The Bouguerplatte can be applied to field measurements and marine measurements.

Country measurement

The mass excess of an infinitely extended plate of height h is subtracted from the measurements. The density of the Bouguerplatte is inferred from the local geology. From this we obtain the Bouguer correction. In a mass excess obtained a positive Bouguer anomaly.

Marine measurement

The sea level is chosen as the reference level. In this case, free -air gravity and Bouguer anomaly are identical. A reduction to a reference level is unnecessary. However, it applies an inverse Bouguerplatte, since the density of the water is lower than the crust. The missing mass is balanced between the seabed and the reference level. The bathymetry has a great influence on the measurement. For this reason, the complete Bouguerplatte is preferred.