Earth is layered like an onion, with a thin outer crust, a thick viscous mantle, a fluid outer core and a solid inner core. Within the mantle, there are two massive blob-like structures, roughly on opposite sides of the planet. The blobs, more formally referred to as Large Low-Shear-Velocity Provinces (LLSVPs), are each the size of a continent and 100 times taller than Mt. Everest. One is under the African continent, while the other is under the Pacific Ocean.
Click here for original story, Study of two blobs in Earth’s mantle shows unexpected differences in height, density
Source: Phys.org