Gravity Method


The force of gravity is not uniform over the whole surface of the earth; it is actually slightly stronger where the underlying rocks are more dense and slightly weaker where they are less dense. The difference is tiny, but can be measured and mapped, giving the geophysicist another weapon in his arsenal.

Gravity surveys use extremely sensitive balances to detect the variations in density of the underlying rocks. They can be useful in conducting a rapid reconnaissance survey of an area to delineate major rock types. This information can help to indicate areas favorable to exploration by other methods. They can also be used in more detailed exploration to detect mineral deposits, which are commonly denser than the rocks that surround them.