* Low rigidity: This means it can flow, albeit very slowly, like a very viscous fluid. This flow is driven by convection currents within the mantle.
* High viscosity: While the asthenosphere flows, it's still very thick and resistant to movement.
* Depth: It is generally located between 100 to 410 km (62 to 255 miles) below the surface.
Key roles of the asthenosphere:
* Plate tectonics: The asthenosphere's slow movement acts as the driving force behind plate tectonics. The rigid lithosphere (which includes the Earth's crust) "floats" on top of the asthenosphere, and the movement of the asthenosphere causes the plates to move.
* Volcanism: The partially molten nature of the asthenosphere contributes to volcanic activity. Magma, which originates from the mantle, often rises through the asthenosphere and can erupt at the Earth's surface.
In summary: The asthenosphere is a vital layer in Earth's structure, responsible for driving key geological processes like plate tectonics and volcanic activity.