Scientists from the Princeton University, US, and the Institute of Geodesy and Geophysics in China have discovered gigantic mountains in the Earth’s mantle. This discovery reported in February 2019 could change our understanding about the formation of the planet. The study was published in the journal Science.
earth is generally classified into three main layers: (a) crust—the outermost layer of the earth, (b) mantle—which lies between the crust and the core, and is divided into upper and lower mantle, and (c) core—the deepest zone of the earth which is again divided into the outer and inner core. According to the new discovery, there are several other layers that scientists have identified within the Earth.
Scientists used data from an enormous 8.2 magnitude earthquake which shook Bolivia in 1994, as earthquake waves travel in all directions and can travel through the core to the other side of the planet. The technology is based on the waves basic property of being able to bend and bounce. The earthquake waves travel straight through homogenous rocks but reflect or refract when they encounter any boundary or roughness. All objects have surface roughness and, therefore, scatter light, and the scattering waves carry the information about the surface’s roughness. Scientists made use of computer simulations to understand the complicated behaviour of scattering waves in the depth of the Earth.
Using this process, scientists found mountains and other topography on a layer located 660 km straight down which separates the upper and lower mantle. Without giving a formal name to this layer, they called it ‘the 660-km boundary’. The boundary is rougher than Earth’s surface layer. Scientists also examined a layer 410 km down at the top of the mid-mantle ‘transition zone’, but the surface there was not similarly rough. However, the scientists couldn’t determine the height of these mountains, but they predict that these mountains could be bigger than anything on the surface of the Earth.