Looks like earthquake activity is heating up again. A funny thing happened in North America during the 1800's. There were a number of big earthquakes popping off, and then nothing. For most of our 'modern' period, we have had nothing.
That's because when a big earthquake shoots it's load, there is a stress shadow which can last more than a hundred years. Thus, earthquakes are suppressed over a rather large area around each expended fault zone. Now, I know most people with say " So? Enjoy the moment!", but it gets us worry-warts worried.
Perhaps this 'vacation' is coming to an end. Who knows?