Hi Todd, unless I'm getting confused, you have not been posting much or at all until this week for the last good while, so good to have you back. Canie....you probably know that great earthquakes do ring the earth like a bell: set off free earth oscillations. Lowell W. introduced me to this concept (which is well known by seismologists). Whether it has anything to do with later quakes is another story.
Todd: are you sure it has been quiet for 4s? You could have Roger graph this up, but he would have to remove aftershocks (and maybe far field aftershocks).
Chris