With a few tricks borrowed from the oil industry, scientists are hoping to one day better understand why earthquakes start and stop.
Geologists would love to know what controls earthquakes. But one of the best ways to answer that question - drilling into faults - is expensive and difficult. An easier alternative is to study faults exposed on Earth's surface, and look at "fossilized" earthquakes preserved along the faults.
But faults can be several feet wide and filled with crushed-up rock, or they can be inch-thick cracks. How does someone walk up to a crack, point a finger at it and determine an earthquake occurred there?
Sometimes, the tremendous heat created during an earthquake melts rock inside a fault. "That was the gold standard," said Heather Savage, a geophysicist at Lamont-Doherty Earth Observatory in New York. "When you get the melt, it means the fault slipped fast."
(Faults get hot because of friction. Just as rubbing your hands warms them on a winter's day, earthquakes heat the Earth when two sides of a fault slide past each other during a quake.)