pl note a major after shock of 6.1 occurred on Wednesday ie 8 days after major quake of 7.2.
As check my theory given on this blog. Moon plying the major role in quakes, major aftershocks occur after 7 and half days,because Moon acquires next potent position 90 degrees apart of original major quake position
slowly the potency of combination reduces and after 15 days (180 degrees apart) it may fade away.
regards Amit dave