Chinese official disputes report linking fatal earthquake in Ludian and filling of reservoirs

A Chinese earthquake official refuted a report by a leading scientific journal that hinted possible links between a fatal quake last month and gigantic reservoirs.

When choosing the site of [a] hydropower station, our government would make [a] seismic safety evaluation,” Xu Xiwei , deputy director of China Earthquake Administration’s Institute of Geology in Beijing, told news portal thepaper.cn yesterday “so the hydropower station would be sited away from [an] active fault and will not be constructed in an area that’s prone to earthquakes.”

Xu’s comment came after a report by Nature, a prominent scientific journal on September 10, cited an analysis by Fan Xiao, an engineer at the Sichuan Bureau of Geology and Mineral Resources in Chengdu, as saying that crude data he collected showed a rough correlation between a 6.5-magnitude earthquake in Ludian, Yunnan province last month in which more than 600 people were killed and the filling of Xiluodu reservoir on the upper Yangtze River.

Xu said some earthquakes – mostly of middle- or small-scale – might be possibly triggered by dams, “but the affected regions would be within 10 kilometres surrounding the reservoirs,” Xu told thepaper.cn, “as the distance between the epicentre of Ludian quake and the dam is about 40 kilometres, the influence would be not big”.

The Nature report cited Fan’s analysis, in which he said he took seismic readings from January 2010 to July this year and discovered that “small quakes became more frequent in late 2012 and continued until the end of the period… [when] heightened activity roughly correlates with the reservoirs being filled”, including Xiangjiaba on the Jinsha River.

Fan’s analysis said the most affected areas of reservoir filling include the one close to a fault whose rupture led to the Ludian earthquake.