There's the
Vialls link.
It's been known for a while that pumping water or oil out of (or into) can upset them.
http://www.kron4.com/Global/story.asp?S=3820767
http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2001/08/23/MN140361.DTL
http://news-service.stanford.edu/news/2002/july10/pilothole-710.html