Seismic waves reveal giant structures deep beneath Earth’s surface
Menu EARTH By D_R_Foundation Deep beneath the Marquesas Islands in the South Pacific is a giant structure near Earth’s core Seismic wave data has revealed giant structures 2900 kilometres beneath the surface of Earth, at the boundary between Earth’s molten core and solid mantle . Analysing data from hundreds of major earthquakes, Doyeon Kim at the University of Maryland and his colleagues have found a new structure beneath the volcanic Marquesas Islands in the South Pacific Ocean. The structure, known as an ultra-low velocity (ULV) zone, is about 1000 kilometres in diameter and 25 kilometres thick, says Kim. These structures are called ULV zones because seismic waves pass through them at slower velocities, but what they are made of is still a mystery. They might be chemically distinct from Earth’s iron–nickel alloy core and silicate rock mantle, or have different thermal properties. The researchers discovered the structure while analysing...