How thick is the asthenosphere? — Reading Comprehension

Today, we're going on a journey deep inside our Earth. We're going to learn about a special layer called the asthenosphere. Our Earth is made up of several layers, like an onion. We live on the outermost layer, the crust. Below the crust is a thick layer called the mantle. The upper part of the mantle, just below the rigid crust, is what we call the asthenosphere.

The asthenosphere is a very interesting layer. Unlike the solid rock of the crust and the part of the mantle above it, the asthenosphere is so hot that the rock there can slowly flow, kind of like very, very thick honey or silly putty. This ability to flow is what makes the Earth's tectonic plates (the large pieces of the crust) move around on the surface. Think of the asthenosphere as a giant, slow-moving conveyor belt that the plates ride on.

So, how thick is this squishy layer? Scientists can't just dig down and measure it directly because it's too deep and hot. Instead, they use information from seismic waves, which are vibrations caused by earthquakes. These waves travel at different speeds through different materials. By studying how these waves speed up or slow down as they pass through the Earth, scientists can learn about the different layers and their properties, including how deep they start and end.

Based on these studies, the asthenosphere starts about 100 kilometers (around 62 miles) below the Earth's surface. But it doesn't just stop there! It extends much deeper, all the way down to about 700 kilometers (around 435 miles) below the surface. So, the asthenosphere is quite thick, ranging in thickness from about 600 kilometers (700 km - 100 km).

Fun Fact: The slow movement of the asthenosphere, even though it's only a few centimeters per year, is responsible for huge geological events like mountains forming, volcanoes erupting, and even earthquakes!

Which layer of the Earth is just below the crust?

What is the asthenosphere made of?

How do scientists learn about the asthenosphere?

Compared to the crust, how does the rock in the asthenosphere behave?

The asthenosphere allows the Earth's tectonic plates to:

If seismic waves slow down as they travel through a certain layer, what might this indicate about the material in that layer?

Approximately how far below the Earth's surface does the asthenosphere begin?

If the asthenosphere were more rigid, what might happen to the movement of Earth's plates?