Destructive earthquakes triggered by dam heightening unlikely: researcher

WUHAN, April 8 (Xinhua) -- A project to heighten a dam in central China's Hubei Province is unlikely to trigger destructive earthquakes, an earthquake researcher said Monday.

Greater water storage capacity, a larger permeable area and deeper impact may induce some minor quakes, but destructive earthquakes with magnitudes over 4.7 are highly unlikely, said Wang Qiuliang, an associate researcher with the provincial earthquake bureau.

Wang said the dam was built upon favorable geological conditions with no active fault traversing through the site, and the strongest earthquake induced by the dam occurred in 1973, with a magnitude of 4.7.

To monitor seismic activity near the dam, the province started building a dam-inducted earthquake monitoring system last year, which will be put into operation in July, he said.

Construction of the Danjiangkou Dam, located in the city of Danjiangkou, started in 1958. It was completed in 1973 with a water storage level of 157 meters.

The project to heighten the dam started in 2005 as part of China's south-to-north water diversion project, the largest project of its kind of the world. It is designed to take water from China's longest river, the Yangtze, to arid northern regions, including Beijing, via eastern, central and western routes.

The dam heightening project, expected to be completed this year, will enable the dam to raise its maximum water level from 157 meters to 170 meters.