Lithosphere vs Asthenosphere
We hardly pay any attention to the surface of the earth we live upon and perform all our actions. We take the physical properties of the earth’s crust for granted and assume it to be a spherical ball that has the same surface properties from the top to bottom. However, it is not so and this fact keeps on reflecting itself in the form of earthquakes and volcanoes that we witness. Scientists divide the surface of the earth from the crust we walk upon to the centre or the innermost point of the earth into different layers. Lithosphere and Asthenosphere happen to be the important two layers of the inside of the earth that confuse people because of their similarities. However, this article intends to highlight the differences between these two different layers that make up the part of the interior surface of our earth.
Lithosphere
From the surface of the earth we stand upon down to the first 100 km inside it is the layer of the earth that is known as Lithosphere. Thus, the outermost layer of the earth that is visible to us in the form of the surface is called Lithosphere. It is composed of all the rocks and other solid surface that we see on the surface in the form of soil, hills, and mountains. The word Lithosphere comes from the Greek Litho that literally means a rock. This layer of the earth is also divided into two types, one that we see and walk upon and the other beneath the waters of the oceans. Thus, there are the continental as well as oceanic layers in the form of Lithosphere. The reason why it is rigid and cold is because of the fact that Lithosphere is comprised of hard rocks.
Asthenosphere
The layer of earth that is just below Lithosphere and goes deeper inside the surface is known as Asthenosphere. The balance between pressure and temperature is such that the rocks in this layer of the earth have little strength, and they behave like butter under a knife. This is the part of the mantle that slows down seismic waves as it consists of molten rocks. If you have ever dunk slush, you can understand the condition of the rocks inside this layer of the earth. If we consider the entire mantle as whole, Asthenosphere comprises just over 6% in volume, but it is very important in tectonic plate movement as because of the liquidity of this layer, the overlying layer called Lithosphere is able to move.
What is the difference between Lithosphere and Asthenosphere?
• The difference between lithosphere and Asthenosphere pertain to their compositions.
• While lithosphere is hard and rigid, Asthenosphere is a layer made up of molten rocks.
• Lithosphere stretches from the top of the earth’s crust down to first 100 kilometers while Asthenosphere lies beneath lithosphere
• Rocks are under severe pressure in Asthenosphere, whereas they face much less pressure in lithosphere.
• The mineral composition of lithosphere is varied as it contains more than 80 minerals whereas Asthenosphere is mainly comprised of silicates of iron and magnesium.
• The depth of the lithosphere is about 100 kilometers, whereas the depth of Asthenosphere is 400-700 kilometers.