lowshearvelocity

Low shear velocity refers to a region within the Earth's mantle where seismic shear waves travel at a slower than average speed. This phenomenon is primarily detected through seismic tomography, a technique that uses seismic waves generated by earthquakes to image the Earth's interior. Shear waves, also known as S-waves, are seismic waves that move rock particles perpendicular to the direction of wave propagation. Their velocity is influenced by the material properties of the rock, specifically its rigidity and density.

Regions of low shear velocity are generally interpreted as areas where the mantle rock is hotter and/or partially molten. Higher temperatures reduce the rigidity of the rock, causing seismic waves to slow down. The presence of even a small amount of melt can significantly decrease shear wave velocity. These zones are often found above mantle plumes, which are upwellings of hot material from deep within the Earth, and in subduction zones where one tectonic plate is forced beneath another.

The study of low shear velocity regions is crucial for understanding mantle dynamics, plate tectonics, and the processes that drive volcanic activity. By mapping these anomalies, scientists can infer the location and extent of hot spots, the pathways of mantle convection, and the thermal state of the Earth's interior.