What is the importance of density when exploring earths interior?
As you go deeper into the interior of Earth the density of the rocks increases. This is due to the pressure of the overlying rock. While density of individual minerals doesn’t change, tiny spaces between them are forced to close, decreasing what little porosity there once was in the rocks. If you are a petroleum geologist that porosity decrease is bad, because pore spaces in rocks is what holds oil or gas (fractures, or breaks in rocks hold oil and gas, too, and these may increase at depth). A side effect of the increase in density is that seismic waves can be refracted (bent) by changes in rock density. If the seismologist miscalculates or mis-estimates the density changes with depth then his results may be in error. These are the effects I can come up with easily. I hope they help you.
