Dips in Earth's gravitational field tied to 'slab graveyards'
Scientists have unearthed a new explanation for several low-gravity spots detected around the world. They’re blaming the anomalies on vast “slab graveyards” that lie buried deep near the planet’s core.
When these slabs of rock were buried long ago, they released water that reduced the density of overlying rock, Caltech geophysicist Michael Gurnis and his colleagues reported online May 9 in Nature Geoscience. Low-density rock has less mass, and so less gravitational pull.
Scientists had previously noticed that gravity’s tug is smaller where tectonic plates,