How the earth heals itself after an earthquake

For the first time, scientists have watched the Earth heal itself after an earthquake.

The process is similar to the body repairing a cut, researchers from China and the United States reported on June 27 in the journal Science. During an earthquake, the ground tears apart along a fault, leaving a jagged series of fractures. After China’s devastating magnitude 7.9 Wenchuan earthquake in 2008, fluids filled the fractured fault, like blood gushing into a wound, the team found by drilling into the fault. Within two years — a blink of the eye in geologic time — the fault was speedily knitting itself back together, closing gaps through a combination of processes. But the gashes occasionally reopened when damaged by shaking from distant earthquakes, the study reports.