Measurements in southern China find quick healing of fractured rock
After an earthquake, fault zones may need no more than a couple of years to regain their strength, research suggests. But the recovery is not without setbacks: Large, distant quakes can redamage fragile faults and prolong healing.
A fault weakened by a rupture won’t begin to build up stress again until it’s strong enough. So the new findings, published in the June 28 Science, should help researchers understand the timing of earthquake cycles in a fault zone.
After a magnitude 7.9 earthquake devastated southern China in 2008, scientists drilled a borehole 1,201 meters into the Longmen Shan fault zone to monitor the healing process. Researchers have previously analyzed fault strengthening in the laboratory or with surface measurements. But this is the first time anyone has peered directly into a fault to observe recovery. “We’re very hard up for evidence about what’s happening down there,” says seismologist John Vidale of