300px|thumb|upright=1.6|The asthenosphere shown at a subduction boundary
The asthenosphere is a layer of Earth's upper mantle that lies beneath the rigid tectonic plates and behaves in a more plastic, flowing manner. It's important because it allows the tectonic plates above to move and shift, which drives major geological processes like earthquakes, volcanic activity, and the formation of mountains and ocean basins.
AI-generated from the Wikipedia summary — may contain errors.
300px|thumb|upright=1.6|The asthenosphere shown at a subduction boundary
The asthenosphere () is the mechanically weak and ductile region of the upper mantle of Earth. It lies below the lithosphere, at a depth between c. below the surface, and extends as deep as . However, the lower boundary of the asthenosphere is not well defined.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).