Japanese geologists say they have located vast deposits of rare earth minerals — crucial to the production of high-tech electronics and components of the emerging green energy industry — 2 to 4 miles below the surface of the Pacific Ocean. A team led by University of Tokyo researcher Tasuhiro Kato found as many as 100 billion tons of recoverable minerals at 78 sites in international waters near Hawaii and Tahiti. According to Kato, an associate professor of earth science, just one square kilometer of deposits — which may include such rare earth elements as cerium and praseodymium —Â could supply one-fifth of the current global annual consumption of some rare earth metals. With China accounting for about 97 percent of the world’s rare-earth supplies — and prices rising sharply — companies and nations are racing to find new sources of rare earth minerals, which are used in everything from smart phones to hybrid car batteries; some firms are preparing to begin deep sea mining operations. A report on the discovery was published in the journal Nature Geoscience.