Why study the earths gravity field?
There are several important reasons to study the earth’s gravity field. More particularly, it is VARIATIONS in the gravity field that are important. The most important is in mineral exploration. Small changes in the gravity field indicate variations within the earth’s crust. (For example, the gravity field will be slightly stronger near a large ore body; because the rocks within the ore body are more dense than the surrounding rocks.) Studies to determine such changes are called gravimetric surveys. Incidentally, it is very difficult to measure the earth’s gravity field in absolute terms – results of only about 1 in a million can be achieved. Howwever, determination of changes in the RELATIVE gravity beween places can be much more accurately determined, which makes gravity surveys useful.
