A major earthquake has struck China’s Yunnan province for the second time in just over two months. Last night at 9:49pm (Beijing time), a 6.0-magnitude quake occurred in Jinggu County, Pu’er Prefecture. According to Xinhua News Agency, the current death toll stands at 1, with a further 324 people injured.
The epicenter of the quake was 22 km west-southwest from Weiyuan Township and it struck at a focal depth of 10.9 km beneath the surface. Luckily, the earthquake occurred in a sparsely populated area of the province, and there have a relatively few casualties as a result. However, according to local authorities, a total of 92,700 people were affected by the quake, with 56, 880 of them being relocated. Within hours of the earthquake, thousands of search and rescue personnel had been transported to the county and were undertaking operations.
Aftershocks were felt in the area for hours after the initial quake, and the largest registered at 4.2 on the Richter scale. Tremors were also felt throughout the province, with friends of East by Southeast feeling the earthquake in Kunming, almost 400 km away from the epicenter.
Closer to the center of the earthquake are a number of major hydropower dams. According to ExSE’s research, a total of 10 hydropower stations are in a 200 km radius of Weiyuan Township, some of them high-wall dams with installed capacities of over 1000 MW. The closest is the 1,350 MW Dachaoshan Dam (大朝山大坝）, located just 60 km from the earthquake’s epicenter and . Yayangshan Dam （崖羊山大坝）, the first in a 1,300 MW, seven-dam cascade on Yunnan’s Black River (墨江) is 85 km away and The third closest, the Nuozhadu Dam (糯扎渡大坝), is located 118 km from the earthquake’s epicenter.
Southwest China is a seismic hotbed where earthquakes are quite common and in the past 6 years alone, there have been a number of major earthquakes in the region. The Wenchuan Earthquake (2008) killed more than 70,00 people while more recently, earthquakes in Ya’an, Sichuan (2013) and Ludian, Yunnan (August 2014), killed 220 people and 617 people, respectively. At the same time, Southwest China’s mountainous geography and wealth of major rivers makes it ideal for hydropower development.
In the past 30 years, hundreds of dams have been built in the region, however their placement in a such a seismically active area is problematic. First, there is evidence to suggest that major hydropower dams can be a factor in seismic activity. In the aftermath of the 2008 Wechuan Earthquake, a number of scientists found that the placement of a dam and its large reservoir over an active fault line could have caused the quake. Secondly, dams and reservoirs can sustain major damage in the event of a large earthquake in its vicinity. Following the 8.0-magnitude Wenchuan Earthquake, the Chinese Ministry of Water Resources found that 2,380 dams were damaged.
Yesterday’s quake was of a smaller magnitude than the Wenchuan Earthquake so the potential for damage is smaller and at the time of publication, there have not been any reports of any of the 10 dams in Jinggu County’s vicinity sustaining damage. However, ExSE will continue to cover the aftermath of the Jinggu Earthquake and the recovery and rescue efforts undertaken.