On the Presence of Liquid in Earth's Inner Core

• DOI: 10.1126/science.287.5462.2471
• Publication Date: 2002-07-27T09:40:21Z
• Authors: S. C. Singh; M. A. J. Taylor; J. P. Montagner
• Keywords: 13. Climate action; 01 natural sciences; 0105 earth and related environmental sciences

Seismological studies indicate that the inner core of Earth is anisotropic for compressional waves ( P waves), and has low shear wave ( S wave) velocity, and high seismic attenuation. Using an effective medium theory for composite materials, we show that the presence of a volume fraction of 3 to 10% liquid in the form of oblate spheroidal inclusions aligned in the equatorial plane between iron crystals is sufficient to explain the aforementioned seismic phenomena. Variation of S -wave velocity between the polar axis and equatorial plane is more sensitive to the addition of liquid than that of P waves. The liquid could arise from the presence of dendrites or a mixture of elements other than iron that exist in liquid form under inner-core conditions.