A new wrinkle is all the damaged dams in the region. The authorities reported almost 400, mostly small, dams have been damaged. Obviously, flooding downstream is the immediate danger, but then you also face loss of the reservoirs which may supply drinking water to more distant communities. Plus, some may have hydroelectric plants which would presumably be damaged, too, if a dam breaks.

Shifting focus here--I don't know how seismically active the area around the collosal Three Gorges Dam is, but if that puppy ever broke due to a massive quake (and 7.9 really is massive), that would be catastrophic.