Earthquakes can have a silver—or rather golden—lining. Some six miles underground, water can contain trace amounts of gold and silica. When an earthquake occurs, voids along a geological fault widen suddenly, pressure plummets, and the water held inside turns to steam. Meanwhile, the gold and silica in that water end up on local surfaces, scientists in Australia suggest. It's not much gold, but it can build up over time, LiveScience reports.
The phenomenon can cause gold to "precipitate almost immediately," researchers say, per AFP. And even the smallest earthquakes may be capable of initiating the process. "Given that small-magnitude earthquakes are exceptionally frequent in fault systems, this process may be the primary driver for the formation of economic gold deposits," says one of the researchers. The theory could also explain why gold is often associated with quartz, as in the 19th-century US gold rush.