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

http://dutchsinse.com/5222015-erupting-volcano-earthquakes-off-west-coast-of-oregon-whole-coast-moved-over-48-hours/