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Although having a composition similar to Earth's solid inner core, the outer core remains liquid as there is not enough pressure to keep it in a solid state. Seismic inversions of body waves and normal modes constrain the radius of the outer core to be 3483 km with an uncertainty of 5 km, while that of the inner core is 1220±10 km. [7]: 94
Travel-time curve is a graph showing the relationship between the distance from the epicenter to the observation point and the travel time. [2] [3] Travel-time curve is drawn when the vertical axis of the graph is the travel time and the horizontal axis is the epicenter distance of each observation point. [4] [5] [6]
Earth's outer core is a fluid layer about 2,260 km (1,400 mi) in height (i.e. distance from the highest point to the lowest point at the edge of the inner core) [36% of the Earth's radius, 15.6% of the volume] and composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. [31]
The molten section of the outer core is thought to be about 700 °C (1,292 °F) hotter than the overlying mantle. It is also denser, probably due to a greater percentage of iron. This distinct boundary between the core and the mantle, which was discovered by the change in seismic waves at this depth, is often referred to as the core–mantle ...
S-waves: Do not propagate as the outer core is liquid [28] [27] Inner core: Average P-wave velocity: 4.4 km/s [27] Average S-wave velocity: 2.4 km/s [27] The sharp decline in P-wave velocity at the mantle-core boundary suggests a liquid outer core, transitioning from 7.7 km/s in the mantle to 4 km/s in the outer core. [59]
The core–mantle boundary (CMB) of Earth lies between the planet's silicate mantle and its liquid iron–nickel outer core, at a depth of 2,891 km (1,796 mi) below Earth's surface. The boundary is observed via the discontinuity in seismic wave velocities at that depth due to the differences between the acoustic impedances of the solid mantle ...
[2] [3] [4] The thickness is 220 km [citation needed]. It appears beneath continents , but not usually beneath oceans , [ 5 ] and does not readily appear in globally averaged studies. Several explanations have been proposed: a lower limit to the pliable asthenosphere , a phase transition , [ 6 ] and most plausibly, depth variation in the shear ...
The Earth's mantle is a layer of silicate rock between the crust and the outer core. Its mass of 4.01 × 10 24 kg is 67% the mass of the Earth. [1] It has a thickness of 2,900 kilometres (1,800 mi) [1] making up about 84% of Earth's volume. It is predominantly solid, but in geological time it behaves as a viscous fluid