News of the WeekEarthquake Recovery

Slew of Landslides Unmask Hidden Geological Hazards

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Science  05 Nov 2010:
Vol. 330, Issue 6005, pp. 744
DOI: 10.1126/science.330.6005.744

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Summary

Just before midnight on 7 August, heavy rains in the mountains north of Zhouqu, in western China's Gansu Province, unleashed a torrent of mud, boulders, and rubble on the slumbering town. Like many settlements in mountainous regions, Zhouqu is built on an alluvial fan from earlier debris flows. The August disaster was the 12th damage-causing event since 1823. Researchers estimated that some 25 million cubic meters of loose rock and sediment had accumulated in two gullies north of town. Human activities like quarrying contributed to the precarious mass, but most of it, researchers believe, was deposited by landslides and rockfalls after a big earthquake in 1879. The findings suggested that debris flows could strike more than 100 years after a major quake.