The Federal Reserve's interest rate decision in December was very well telegraphed and understood. So it, per se, doesn't really count as a ‘shock’. It resulted in the expected sorts of effects – like a turnaround in earlier international capital flows to emerging markets. Some of these actually began ahead of the event itself.
At the same time, though, the very low rates of inflation and still very gradual pace of economic growth have led other central banks to seek further easing of monetary policy. Balance sheet measures have been stepped up and several European jurisdictions have applied negative interest rates to parts of banks' reserve holdings at the central bank. The same is happening in Japan.