Rereading Liaquat Ahamed's Lords of Finance, I came across the interesting phrase "the obverse of a bubble." It's what the coordinated actions of the advanced economies' central banks today were designed to prevent.

During boom times when speculative bubbles form, central banks are supposed to "take away the punch bowl." During times of gloom, when interest rates of Italian, Spanish and German debt are going up beyond sustainable levels, central banks are supposed to provide liquidity.