The suspense!

So, this tremor... how strong is it? Is it a few-second shake that would make everyone think, "Oh, it's just an aftershock from some earthquake in California. Moving on"? Or is it full-on earthquake that will make everyone go, "Holy crap, what's going on, the world is ending, RUN!!"? Or is it a series of shakes, each one stronger than the last? I don't want to over- or under-react to the tremor.