Geophysics S-waves in the outer core. This indicates that the outer core is liquid, because liquids cannot support shear. The outer core is liquid, and the motion of this highly conductive fluid generates the Earth's field. The inner core, however, is solid because of the enormous pressure. Reconstruction of seismic reflections in the deep interior indicate some major discontinuities in seismic velocities that demarcate the major zones of the Earth: inner core, outer core, mantle, lithosphere and crust. The mantle itself is divided into the upper mantle, transition zone, lower mantle and "D′′" layer. Between the crust and the mantle is
International Association for Engineering Geology and the Environment International Association for Engineering Geology and the Environment The International Association for Engineering Geology and the Environment (), formerly International Association for Engineering Geology, also known as IAEG (), is an international scientific society which was founded in 1964. It is affiliated with the International Union of Geological Sciences (IUGS) and has 3,798 members and 59 national groups all over the world. The association aims to promote and encourage the advancement of engineering geology through technological activities and research. At the same time it strives to improve teaching and training in engineering geology, and to collect, evaluate and disseminate the