What are some interesting facts about asthenosphere?

Answer 1

by low-density, semiplastic (or partially molten) rock material chemically similar to the overlying lithosphere. The upper part of the asthenosphere is believed to be the zone upon which the great rigid and brittle lithospheric plates of the earth's crust move about (see plate tectonics). The asthenosphere is generally located between 45—155 miles (72—250 km) beneath the earth's surface, though under the oceans it is usually much nearer the surface and at mid-ocean ridges rises to within a few miles of the ocean floor. Although its presence was suspected as early as 1926, the worldwide occurrence of the plastic zone was confirmed by analyses of earthquake waves from the Chilean earthquake of May 22, 1960. The seismic waves, the speed of which decreases with the softness of the medium, passed relatively slowly though the asthenosphere, thus it was given the name Low Velocity zone, or the Seismic Wave Guide (see seismology). Deep-zone earthquakes, i.e., those that occur in the asthenosphere or below it, may be caused by crustal plates sinking into the mantle along convergent crustal boundaries.

Answer 2

What Is The Asthenosphere?

Before we can learn everything important about the asthenosphere, we need to know exactly what it is! The asthenosphere is a layer of rock that is found underneath the crust of the Earth. The solid crust of the Earth and its rocky upper mantle (also known as the lithosphere) meet the lower layers of the mantle at the asthenosphere, making it an important part of the structure of the Earth.

Ten Asthenosphere Facts To Rock Your World

You'll have to put on your scientist hat to get to the core of these intriguing asthenosphere facts

) The asthenosphere is a layer of semi-molten rock. The temperature is just below the melting point of rock, so it's too hot to be solid like the crust, but still too cool to be liquid. It's also under a huge amount of pressure, so it has all kinds of strange properties. It can flow like a liquid, break like a solid and transmits seismic waves at different rates to the other layers. It may even be responsible for earthquakes and volcanoes!

2. The asthenosphere sits beneath the lithosphere (the solid outer layer that forms the Earth's surface), and forms part of the upper mantle. This can be anywhere between 100 km and 700 km beneath the Earth's surface. Whether or not a bit of rock counts as part of the asthenosphere is decided by its temperature. To count as part of the asthenosphere, the rocks' temperature has to have reached at least 1300°C.

Although Joseph Barrell worked out that the asthenosphere must exist in 1914, we didn't prove it was there until 1960, when an enormous earthquake hit Chile. The seismic waves created by the earthquake were so strong that scientists were able to measure them closely and prove that they moved differently through the asthenosphere than in other layers of the Earth.

5. The name asthenosphere comes from the Greek word asthenia, meaning weak. Barrell called it the asthenosphere because its materials are weak compared to the more solid rocks in the lithosphere.

6)The asthenosphere is the reason plate tectonics work. Tectonic plates are large pieces of rock that make up the surface of the earth, a bit like puzzle pieces. They float on top of the asthenosphere. Because the asthenosphere is not completely solid, convection currents within it move each plate at a slightly different rate and direction. When a plate bumps into or slides along another plate, it causes shock waves, also called seismic waves. This movement is usually felt on the Earth's surface as an earthquake.

Scientists can measure how thick the asthenosphere is by measuring seismic waves. Yes, the same ones that cause earthquakes. Because the rocks in the asthenosphere are half-liquid and half-solid, waves called s-waves travel through it more slowly than they do other layers. By measuring how fast s-waves move, scientists can tell how deep the asthenosphere goes at different points round the earth.