Letter: It's dam dangerous in the Three Gorges

From John Prewer

Your interview with Dai Qing
(7 April, p 42)
made no mention of what may
well turn out to be the worst of all the threats presented by the Three Gorges
Dam—dam-induced seismic activity.

Last month I spent ten days in Chongqing as a guest of the local university,
where I met members of staff from the department of civil engineering. They told
me that Chongqing lies in a seismically active zone.

Knowing that seismic activity often follows the construction of large
dams—even in areas where there are no records of any previous seismic
activity—I asked my hosts what level of dam-induced seismic activity was
expected, and what measures had been taken to mitigate its effects. I
particularly wanted to find out about any safety plans for the older parts of
Chongqing, where crumbling, grossly overcrowded blocks of flats would be heavily
damaged by even minor earthquake shocks.

I suspect my questions touched a politically sensitive nerve,
because—though I repeated them on several different occasions—they
were, very politely, never answered.

Bapchild, Kent