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The asthenosphere (from Ancient Greek ἀσθενός (asthenós) 'without strength') is the mechanically weak [1] and ductile region of the upper mantle of Earth. It lies below the lithosphere , at a depth between c. 80 and 200 km (50 and 120 mi) below the surface, and extends as deep as 700 km (430 mi).
Interaction of the asthenosphere, lithosphere, and surface though the mantle process of subduction at an oceanic-continental plate boundary. Volcanism which originates from the mantle occurs on the surface. Interaction of the asthenosphere, lithosphere, and surface through the mantle process of slab break-off. Grey indicates crust, purple ...
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 environment. [1]
Below the asthenosphere, the mantle is again relatively rigid. The Earth's mantle is divided into three major layers defined by sudden changes in seismic velocity: [ 6 ] the upper mantle (starting at the Moho, or base of the crust around 7 to 35 km [4.3 to 21.7 mi] downward to 410 km [250 mi]) [ 7 ]
At the top of the world in the middle of the Arctic Ocean lies the geographic North Pole, the point where all the lines of longitude that curve around Earth from top to bottom converge in the north.
In geology, the low-velocity zone (LVZ) occurs close to the boundary between the lithosphere and the asthenosphere in the upper 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.
The solar intensity decreases as the latitude increases, reaching essentially zero at the poles. Longitudinal circulation, however, is a result of the heat capacity of water, its absorptivity, and its mixing. Water absorbs more heat than does the land, but its temperature does not rise as greatly as does the land.
A "Blue Norther" is expected to sweep through the central U.S. this weekend, bringing sudden, sharply colder air to the Plains states. (MAPS: Current Temps | 10-Day US Forecast Highs/Lows)What is ...