On Bitstamp, BTC-e, and Bitfinex, there was a surge in volume (peaking at 300-700 BTC/min) while the price was shooting up, but when the rally stalled then volume dropped again to the very low levels it had before (10-30 BTC/min).

On Huobi and OKCoin, volume surged to about the same levels (~600 BTC/min) during the rally, but then it remained high (~120 BTC/min) while the price wandered between ~3800 and ~3820.

Need I say that I see that as evidence that the rally happened in China, and the trades in the West were mainly arbitrage?