"An important seismic event imperceptible to humans..."
Just keep an eye on your local rodents. When you see rats scrambling for safety, you can be assured something big is coming your way. (And I don't mean Fat Teddy!)
Don't ask me how I know this, as my reasoning skills are imperceptible to other humans. ;)
Oh Great! I live 30mi East of Seattle, and I saw two rats cross the road today heading NE, I also saw the same thing last week.