Outer coreThe outer core is a liquid iron-rich alloy between depths of about 2,891 and 5,149.5 km. Motion of this electrically conducting fluid sustains Earth’s magnetic field. Shear waves cannot travel through it.Earth’s interiorCrustUpper mantleLower mantleOuter coreInner coreInnermost inner core (IMIC)Beneath the seafloorNASA · Earth