The deadliest earthquake in modern times killed some 244 000 people in Tangshan, an industrial center about 150 km east of Beijing. Tangshan sits on what ought to be solid ground—the North China craton—but on 28 July 1976, a 7.6-magnitude earthquake struck. Now, 30 years later, understanding intraplate earthquakes such as the one that devastated Tangshan is a key thrust within a set of new Earth sciences initiatives for northern China.
“We have a lot of hypotheses, but we don’t know exactly why earthquakes happen in this kind of place,” says Mian Liu, a geoscientist at the University of Missouri-Columbia. “It’s not like the interplate motion in California, Indonesia, or Japan. Those places are tectonic boundaries.” Intraplate earthquakes occur less frequently, says Eugene Schweig of the US Geological Survey, who studies the New Madrid seismic zone in the North American craton. “And when they happen on these stable continental areas,...
