Intraplate earthquakes

China’s mega-project to investigate the North China craton, including intraplate earthquakes—those occurring in the continental interior rather than at tectonic plate boundaries—got the green light this year (see Physics Today, December 2006, page 31 ). The project has $20 million over five years, and Chinese geoscientists are keen on international collaborations; US funding agencies are already responding with thumbs up.

Next May the first in a series of workshops for geoscientists from the US and China, sponsored by NSF and the US Geological Survey, will be held in Boulder, Colorado. The topic hasn’t been narrowed yet, says Mian Liu, a geoscientist at the University of Missouri–Columbia, but will include active tectonics.

Liu is also the lead on a recently awarded $2.2 million grant from NSF for studying spatiotemporal patterns of large intraplate earthquakes in North China. Liu and colleagues hope to figure out, for example, why intraplate earthquakes migrate in time and space—in contrast to interplate earthquakes, which tend to recur in specific fault zones. They also aim to determine why the incidence of large earthquakes in the North China Plain is rising, while the neighboring Shanxi-Weihe rifts, an area that was rocked more than 30 times by earthquakes of magnitude 6.5 or greater since 1303, including the deadliest earthquake on record, in 1556, has been largely quiescent over the past two centuries. The researchers will work with partners from China.