Big Quakes Trigger Small Ones—Not Other Big Ones

Over the past 15 months, large earthquakes have struck China, Haiti, Chile, New Zealand, Japan, and Burma. But those quakes weren't connected, and they won't trigger any other big ones, seismologists say. A new study shows that, even when they seem linked, large and distant quakes likely aren't—and while they can trigger smaller quakes, sometimes even in far-away locations, they won't trigger other big quakes.

It has long been known that a major quake, as one USGS geophysicist says, "rings the earth like a bell." The resulting quakes, triggered by bursts of energy, can occur many miles away—after a 1992 7.3-magnitude temblor in California, quakes rumbled all over the Western US, and the geyser schedule at Yellowstone, some 680 miles away, was altered. But in order to trigger a large quake, sustained pressure is needed. The bottom line? Californians needn't worry that the Japan earthquake, or any of the other recent quakes, will trigger a higher seismic risk in their state, the Wall Street Journal reports. (More California earthquake stories.)