SAN FRANCISCO — Deep under Earth's surface, earthquakes rumble in the mantle's transition zone, the area that divides the upper mantle from the lower. Liquid in the mantle is thought to play a part in driving those deep earthquakes, but until now, no smoking gun could prove that fluid was present at those depths.
Now, scientists think they may have found evidence of fluid in an unlikely place: inside superdeep diamonds.
https://www.foxnews.com/science/diamonds-buried-400-miles-below-surface-could-explain-mysterious-earthquakes