Gradients of Gravity

quantities that show the rate of change of gravity in the directions of the rectangular coordinate axes associated with the earth’s surface (a vertical and two horizontal). Gradients of gravity, corresponding to idealized models of the earth with a regular shape and interior structure are called normal. The largest of these—the standard vertical gradient of gravity—equals 3,086 Eötvös units on the average for the whole earth. Anomalous changes in vertical and horizontal gradients of gravity can reach hundreds of Eötvös units. Horizontal gradients of gravity are measured by gravitational variometers. The values of the second gradients of gravity, which are used in gravimetric surveying, are calculated from the observed gravity anomalies, or first gradients of gravity.