I feel the earth move under my feet

We had a couple of earthquakes recently. The first at 2:52 am was strong enough to wake us up. I was at work for the second and felt the building sway. We are on the 13th floor so it was quite the sway...I'm glad that the buildings are made to withstand earthquakes.

Someday we are going to get the next Big One here which'll be scary. Do you think that a bunch of small earthquakes heralds the coming of the Big One or is it letting out pressure so that we don't get the Big One.