No such thing as "usual" when it comes to tremors, in this area at least.
There have been at least seven in the last couple of days, the last one woke me up at 0545 this morning.
One year, sometime between the previous local major event in 1997, and the mega-shake in 2010, we had 2 or 3 months of tremors, at least one almost every day. Then they stopped.
Chileans, (and I must admit me as well now), have a mild psychosis about these events, as you are never sure at the outset whether a tremor is going to be just a rumble and a gentle shake or is the start of something bigger.