They certainly do not lack volatility during US hours - that's insane, who told you that?
You see USD in the currency pair, yes - when do you think the bulk of US dollars moves?!
Sure, fx markets are known for waking up with the initial moves during European hours but the same happens again when there is US news, stock markets moving, etc.
thanks for the reply. all of the written forex guides on babypips and some of the guides on forex factory said the best time to trade those pairs (because of increased volatility) was during those hours.