A blast from the past: October 17th, 2011, which seems like longer than 6 weeks ago:
In just 12 hours, there was not one, but two ~20k bitcoin dumps, and wild price swings from 3.5, to 2.4, back to 3.3, and back down to 2.3.
Not surprisingly, trade depth was only 15k btc to move the price $0.50 either way. Nowadays, with bitcoins around the same price, a 15k buy or sell only moves the price about a dime with the additional depth (even if it is "just" a big player). Also, speculators are doing a great job of dampening out any oscillations.
Just thought I'd post this for a bit of perspective.