The largest earthquake in the Pacific Northwest occurred in 1700 (we know this from Japanese records describing the resulting Tsunami). This was in the middle of the Maunder Minimum, which was a period of low solar activity.
Meanwhile - whilst googling for the largest known solar storm in the previous 200 years (the Carrington Superstorm, I wanted to see if there were any notable earthquakes that occurred in September 1859)
I came across
this link that has some good plots in it and access to the data, so that one can perform more detailed analysis if one wants to waste time.
It is worth clicking through to see the plots, but I will just leave this quote - which is what many people have been saying, but not with these exact words.
http://www.thesuntoday.org/solar-facts/flares-and-earthquakes/