Large low-shear-velocity provinces

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Large low-shear-velocity provinces (LLSVPs), also called large low-velocity provinces (LLVPs) or superplumes, are characteristic structures within the lowermost mantle, above the Earth's outer core. These provinces are characterized by slow shear wave velocities appearing in seismic tomography assays of deep Earth. The two main provinces are the African LLSVP and the Pacific LLSVP, both extending laterally for thousands of kilometers and possibly up to 1,000 kilometers (620 miles) vertically from the core–mantle boundary. These have been named Tuzo and Jason, respectively, after Tuzo Wilson and W. Jason Morgan, two acclaimed geologists in the field of plate tectonics. The Pacific LLSVP (Jason) is 3,000 kilometers (1,900 miles) across and underlies four hotspots on Earth's crust where mantle plumes are believed to reach to the surface. These provinces represent around 8% of the volume of the mantle, or 6% of the entire Earth. Other names for LLSVPs and their superstructures include superswells...

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