Quote Originally Posted by winger View Post
As mainly an east-coaster, I don't know which plates are next to what are where fault lines are. But I saw a report that the mudslide in Oso was likely the result of a tremor a couple of weeks before. Is that along any of the same ones shaking now?
Nope.

And are these quakes just being mentioned because of the number or is this a cluster that's larger than usual?
It's because of the intensity, primarily. There are small quakes all the time, most not even felt. The one last week was the largest in a while.
It's common with a significant quake to have aftershocks, and sometimes the first quake or first several are actually foreshocks. In June of '89, we had a decent little shaker in the Santa Cruz area (I was living in Santa Cruz then), and it was not until after the big Loma Prieta quake in October of that year that it was recognized as being a foreshock.