NEW YORK, June 22 (UPI) -- A U.S. seismologist says he's determined earthquakes can occur in synchrony, with big quakes triggering other big quakes along the same fault.
Columbia University Professor Christopher Scholz, a seismologist at the school's Lamont-Doherty Earth Observatory, says in nature, random signals often fall mysteriously in step -- fireflies flashing sporadically in early evening soon flash together, and the same harmonic behavior can be seen in chirping crickets, firing neurons, swinging clock pendulums and now, rupturing earthquake faults.
Scholz says when a fault breaks it might sometimes gently prod a neighboring fault also on the verge of fracturing. He finds evidence for synchronized, or "phase locked," faults in southern California's Mojave Desert, the mountains of central Nevada and the south of Iceland.
He identifies strings of related earthquakes, and explains the physics of how faults, separated by up to more than 30 miles and rupturing every few thousand years, might align themselves to rupture nearly simultaneously.
"All of a sudden bang, bang, bang, a whole bunch of faults break at the same time," Scholz said. "Now that we know that some faults may act in consort, our basic concept of seismic hazard changes. When a large earthquake happens, it may no longer mean that the immediate future risk is lower, but higher."
He details his findings in the Bulletin of the Seismological Society of America.