Geologists have a disturbing message for residents slowly rebuilding their lives in China's devastated Sichuan province after May's Wenchuan earthquake: Brace for further rattling.
The quake, which measured 7.9 on the Richter scale and killed at least 70,000 people, has also put undue stress on the Xianshuihe, Kunlun and Min Jiang faults that run through the region. "We tend to think of earthquakes as relieving stress on a fault. That may be true for the one that ruptured," says Ross Stein of the U.S. Geological Survey, "but not for adjacent faults."
Using computer models, geologists report in Geophysical Research Letters that there's as much as a 71 percent chance that a quake of magnitude 6 or greater will occur in the next decade on one of these other geologic faults. There have already been several aftershocks nearly that large on the Longmen Shan fault that triggered the Wenchuan tremblor. The researchers also predict that a series of smaller earthquakes will occur on these adjacent faults.
In the meantime, the rebuilding must be as solid as possible. "Earthquakes do not kill people, buildings do," says Jian Lin of the Woods Hole Oceanographic Institution, who participated in the research.
Adds Stein: "One great earthquake seems to make the next one more likely, not less."