I have not heard of any recent severe earthquakes that would trigger this. True there are after shocks as is often the case with these events, but none so powerful or of the right kind to trigger a tsunami. The tsunami that hit Japan was caused when the whole country lurched suddenly 13 feet to the east and 2 feet downward. Will there be another tsunami? Yes, without a doubt; but as to the timing, that depends on how fast the internal changes inside the earth are transferred to the crust and where this occurs.