asthenoszférán

The asthenosphere is a highly viscous, mechanically weak and ductile region of the upper mantle of Earth. It lies approximately 100 to 300 kilometers (62 to 186 miles) below the surface, between the lithosphere above and the mesosphere below. The name "asthenosphere" comes from the Greek word "asthenes" meaning "weak," a fitting description for this layer.

Unlike the rigid lithosphere, which is broken into tectonic plates, the asthenosphere can flow slowly over geological timescales. This plasticity is a result of high temperatures and pressures within the mantle, which cause the rock to behave like a very thick fluid. Convection currents within the asthenosphere are the primary driving force behind plate tectonics, causing the lithospheric plates to move, collide, and separate.

The asthenosphere's behavior is crucial for understanding earthquakes, volcanic activity, and the formation of mountain ranges. Its ability to deform allows for the movement of the overlying tectonic plates, shaping the Earth's surface over millions of years. The precise depth and thickness of the asthenosphere can vary depending on the tectonic setting and the age of the lithosphere.