What are the two forces that must balance out to maintain a state of isostasy?

Isostasy is the rising or settling of a portion of the Earth's lithosphere that occurs when weight is removed or added in order to maintain equilibrium between buoyancy forces that push the lithosphere upward, and gravity forces that pull the lithosphere downward.

Explanation:

Theory of Isostasy, is a fundamental concept in geology, is based on the opposing influence of two main forces – Buoyancy and Gravity. It is the state of gravitational equilibrium between earth’s crust and mantle, Such that – The crust floats at an elevation that depends on its thickness and density. It is the idea that the lighter crust must be floating on the denser underlying mantle.

Explanation:

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