2 decades ago I did some work on reservoir-induced seismicity, and read quite a few papers on the subject, and probably ran into one or 2 on rainfall and seismicity. The one linked above was talking about shallow seismicity...I think above 4 km...and it is pretty mainstream geology that faults are weaker if pore pressure is higher, and pore pressure is higher if the water table goes up ...if the area of the future earthquake is linked to this (if there are open fractures/highly permeable?
Chris