China links deadly earthquakes to dam sites, showing risks of hydro power

Three Gorges Dam - Hugh

By Arman Kazemi

September 18, 2014

While China chokes on dark air and hastens climate change by producing nearly a third of the world's carbon emissions, it has taken steps to mitigate the effects of its unchecked growth.

A 2013 European Commission report that noted China's culpability on carbon also made note of China’s efforts to mitigate the effects of coal pollution. The country expanded its hydro capacity by 23 per cent in 2012 alone.

Now Fan Xiao, former chief engineer of the Sichuan province’s Regional Geological Survey Team, draws a positive correlation between China’s recent spurt in dam constructions and some of the country’s recent deadly earthquakes.

According to Quartz magazine, hydropower is China’s largest renewable energy source, accounting for about 20 per cent of the country’s installed power capacity

Since it came into power in the 1950s, the People’s Republic of China has built around 22,000 dams, about half the world’s total. Many of these are located in seismically volatile areas — a result of rivers' tendency to form along fault lines.

It is already well known, as an article in the Guardian indicates, that the pressure of increasing water levels along fault lines can induce small to moderate earthquakes.

This fluid pressure may act as a lubricant inside faults, stirring geological formations already strained by tectonic pressure, causing rocks to slip against each other where friction would otherwise have held them in place.

Thus, according to a report on Chinese dams from International Rivers, “the rapid filling of a large reservoir may trigger an earthquake that would have otherwise naturally occurred several if not hundreds of years later.”

Xiao claims this process has been a factor in many of the country’s recent high-profile tectonic events, including the magnitude-7 quake under the Xiluodu reservoir in Sichuan province that killed 170 people in April 2013 and the massive, magnitude-8 earthquake that killed more than 80,000 in Wenchuan County in 2008.

In December 2012, Xiao headed a report that determined, “the mounting body of evidence and analysis indicates that the magnitude 8 earthquake was triggered by the mass loading and increased pore pressure caused by the Zipingpu reservoir.”



Photo Credit: Hugh