12 



METHODS OF GEOPHYSICAL EXPLORATION 



[Chap. 2 



nents of gravity. These forces are frequently referred to as "horizontal 

 directing forces" or "curvature values" since they are related to the curva- 

 ture of the equipotential surfaces of gravity. If a spherical equipotential 

 surface be so placed that its apex coincides with the beam center, the 



' 6nvitif 

 Anoma/i/ 



r0$torinf 

 font of spring 



/ //III 

 lints eftfiul armrthi anoma/i/ 



^V/^^^w^^^^y/>/^'^y7/^^^y/'A^^y/W^y/^^ 



Fig. 2-3. Gravimeter on traverse across anticline (schematic). 



horizontal components of the gravity forces (which at all points are at 

 right angles to the equipotential surface) all point to the axis of rotation 

 and no deflection of the beam takes place. When this surface is curved 

 in a different manner, the horizontal components no longer point in a 

 radial direction; they tend to turn the beam into the direction of minimum 



