Is the big one coming?

There is no doubt that Matt and I have felt some earthquakes lately. In the last few months, there have been several. Last night was the worst one yet, though. I was sitting at the computer, Reagan was asleep in her bed, and Matt was gone to a basketball game in Danville. All of a sudden things started shaking and it took me a second or two to realize what was happening. When I did, I jumped up and into Reagan's room (instinctively) to check on her and make sure the ceiling didn't cave in on her or something. It lasted like 6 seconds maybe, but felt much longer! Reagan slept peacefully through the whole thing, even me loudly busting through her door to check on her. Darn--why can she sleep through a 4.2 mag earthquake, but if I even so much as walk by her door during naps, she wakes up? Afterwards, I did the most logical thing: called my mom in Utah to wake her up and ask her what I should do? (Yeah, I freaked out). I think it scared me because Matt wasn't home. Anyways, my mom reassured me it was no big deal, but I went to bed last night making sure I knew where my 72 hour kit was, that is for sure.

So should we be worried? Everyone has been predicting the big one. Are these tremors precursors to it? Or, as Matt says, are they taking the place of the big one? I don't think anyone really knows.