What is the relation between height h and depth d for the same change in g?

Relation Between Height and Depth for the Same Change in g:
The acceleration due to gravity decreases both when moving above the Earth’s surface (height) and below it (depth). At a height h above the surface, gravity decreases slightly based on the distance from the Earth’s center. Similarly, at a depth d below the surface, gravity decreases because only the mass within the radius (R – d) contributes to gravity.

For the same decrease in gravity at height (h) and depth d, the relation between them can be found by comparing the two effects. It turns out that the change in gravity at a height h above the surface is the same as that at a depth d below the surface if the depth is twice the height. In other words, d = 2h.

This relationship holds true only when the height h is much smaller than the Earth’s radius, as approximations are used in this derivation. Thus, for small heights and depths, gravity behaves symmetrically with this relation.