In short, the theory (or is it a fact??) says that artificial storage of water in high capacity makes the earth surface more porous than what it could afford to be and secondly the sheer weight of water held in the damns is again something that is artificial and together they attract earth quakes.
Damn, it was the dams:
http://www.seis.com.au/Basics/Dams.html
…and another older article from BBC:
http://news.bbc.co.uk/1/hi/sci/tech/1974736.stm
In short, the theory (or is it a fact??) says that artificial storage of water in high capacity makes the earth surface more porous than what it could afford to be and secondly the sheer weight of water held in the damns is again something that is artificial and together they attract earth quakes.