Gravity variations indicate depth to earth’s mantle

Scientists have used gravitational measurements from the low-flying Goce satellite to map the boundary between the earth’s crust and its mantle in unprecedented detail.

The Mohorovicic or “Moho” discontinuity lies 10–70km below the earth’s surface, and marks a distinct change in rock density. By measuring the tiny variations in Earth’s gravitational field that result from the varying density, it is possible to determine the depth of the Moho boundary. The new map clearly shows that the boundary is deepest beneath large mountains and shallowest beneath oceans.