Category: RIS

This could get complicated

Increasing demand for natural catastrophe insurance has provided the world’s largest reinsurer, Munich Re, with its biggest market in the Asia Pacific region: China. But how will Munich Re classify disasters, such as earthquakes, in a country where seismic events are a growing subject of debate as to how many are natural and how many are man-made?

Quake strikes Three Gorges Dam area again

(May 28, 2014) Another earthquake has struck the Three Gorges Dam reservoir region in central China’s Zigui County. No casualties have been reported so far and officials say the dam is operating normally. The 3.4 magnitude tremor which hit early Monday morning, some 23 km from the dam, follows two earthquakes of magnitude above 4.0 and hundreds of aftershocks which shook the same region in late March of this year. The events rank as significant according to Chinese geologist and environmentalist Fan Xiao, who says they are signals that the seismic threat posed by Three Gorges Dam is at its most critical stage now.

More quakes linked to mega-dams

(April 9, 2014) Another earthquake has struck China’s seismically hazardous southwestern region in the same vicinity as one of the country’s mega-dams. Chinese geologist and environmentalist Fan Xiao says there is a “high probability” the Xiluodu dam, China’s second and the world’s third biggest hydropower power plant, triggered the quake.

Three Gorges Dam triggers frequent seismic activities

(April 7, 2014) Chinese geologist and environmentalist Fan Xiao says the recent quakes that struck central China’s Hubei Province in Zigui county — “the first county of the Three Gorges Dam” due to its proximity to the project site — signal that the seismic threat posed by Three Gorges Dam is at its most critical stage now. Reservoir-induced seismicity (RIS) is most likely to occur within a few years, even a decade after initial filling of a dam reservoir to its highest level, due to the time it takes for reservoir water to penetrate deep into seismic faults and fissures before it triggers seismic activity. A 2010 study revealed seismic monitors around the Three Gorges Dam reservoir and in Hubei Province registered 3,429 earthquakes between June of 2003 (when inundation of the reservoir began) and December 31, 2009: a 30-fold increase in seismic frequency over the pre-dam period.