There’s an interesting table of large (>mag 5.0) earthquakes over the past week at the USGS website.
As I write this there are 14 quakes listed in the 7 days before the Sumartran quake, including the 8.1 near Macquarie Island with an average magnitude of 5.55, and an average occurance of 2 per day.
Since then (less than 10 hours) there have been another 14 quakes, with an average magnitude of 6.04 with an average occurence of 33.5 per day, that’s one hell of an increase in activity!