Feb. 13 (UPI) -- Roughly 350 kilometers, or 217 miles, beneath the surface of the Western United States, lies a newly discovered mass of melting carbon. Researchers found the region of melting carbon using the world's largest array of seismometers. The molten belt stretches across 1.8 million square kilometers, or 695,000 square miles.
As carbonates melt deep beneath Earth's surface, they produce unique seismic patterns, which can be measured by the array of seismic sensors. The images yield a map of Earth's upper mantle.