主题：关于汶川地震的MIT说法：2000年至万年一遇的怪地震 -- thacaos

这20多年来，麻省理工学院研究队伍一直都在考察四川省周围地区，不过却从未发现任何大地震可能发生的迹象。因此，该研究队伍认为，今年5月12日在四川省发生的里氏7.9级地震（中国方面测定为8级地震）是意料之外的。

A new analysis of the setting for last month's devastating earthquake in China by a team of geoscientists at MIT shows that the quake resulted from faults with little seismic activity, and that similar events in that area occur only once in every 2,000 to 10,000 years, on average.

Clark Burchfiel, Schlumberger Professor of Geology, and Leigh Royden, professor of geology and geophysics in the Department of Earth, Atmospheric and Planetary Sciences at MIT, have been doing extensive research in that region of China and the Tibetan plateau for more than two decades, but had found no hints that suggested such a large earthquake might strike the area.

The team operated an array of 25 broadband seismograph stations in this region of western Sichuan for more than a year. "Nobody was thinking there would be a major seismological event" in that area, Royden says. "This earthquake was quite unusual," and may have involved a simultaneous rupture of two separate but contiguous faults, she continued.