It's also known that certain types of marine quakes are more frequent at low tide, though the weight differential involved there is orders of magnitude larger t

It's also known that certain types of marine quakes are more frequent at low tide, though the weight differential involved there is orders of magnitude larger than in the case of the CA drought: http://onlinelibrary.wiley.com/doi/10.1111/j.1365-246X.2009.04319.x/abstract http://onlinelibrary.wiley.com/doi/10.1111/j.1365-246X.2009....