I ran across this sight with some interesting insights on earthquakes, swarms and volcanos. He has some comments on cracking that I don’t know enough about to have an opinion on the comments so YMMV.
Since I will be living in Seattle for 2 week per month for work, it has peaked my interest from a emergency preparedness standpoint
Scroll down the page and watch the video. Let me know what you think
edit:corrected the link