Search results
Results from the WOW.Com Content Network
Green curves show hypothetical Earths with density constant (dashed) and decreasing linearly from center to surface (stippled) The preliminary reference Earth model (PREM) plots the average of Earth's properties by depth. [1] It includes a table of Earth properties, including elastic properties, attenuation, density, pressure, and gravity.
Earth's inner structure can be described both chemically (crust, mantle, and core) and mechanically. The lithosphere–asthenosphere boundary lies between Earth's cooler, rigid lithosphere and the warmer, ductile asthenosphere. The actual depth of the boundary is still a topic of debate and study, although it is known to vary according to the ...
Hypsometry (from Ancient Greek ὕψος (húpsos) 'height' and μέτρον (métron) 'measure') [1] [2] is the measurement of the elevation and depth of features of Earth's surface relative to mean sea level. [3] On Earth, the elevations can take on either positive or negative (below sea level) values.
Earth's outer core is a fluid layer about 2,260 km (1,400 mi) thick, composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. [ 1 ] [ 2 ] [ 3 ] The outer core begins approximately 2,889 km (1,795 mi) beneath Earth's surface at the core-mantle boundary and ends 5,150 km (3,200 mi) beneath Earth's surface ...
The mass of the oceans is approximately 1.35 × 10 18 metric tons, or about 1/4400 of the total mass of the Earth. The oceans cover an area of 3.618 × 10 8 km 2 with a mean depth of 3,682 m, resulting in an estimated volume of 1.332 × 10 9 km 3. [8]
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 ...
It is characterized by unusually low seismic shear wave velocity compared to the surrounding depth intervals. This range of depths also corresponds to anomalously high electrical conductivity. It is present between about 80 and 300 km depth. This appears to be universally present for S waves, but may be absent in certain regions for P waves. [2]
Bathymetric charts showcase depth using a series of lines and points at equal intervals, called depth contours or isobaths (a type of contour line). A closed shape with increasingly smaller shapes inside of it can indicate an ocean trench or a seamount, or underwater mountain, depending on whether the depths increase or decrease going inward.