See the chart in this article showing that the actual working monetary base has appreciated much more normally than the traditional monetary base since 2008.
There are several monetary policy tools available to achieve these ends: increasing interest rates by fiat; reducing the monetary base; and increasing reserve requirements.
Other monetary policy tools to expand the money supply include decreasing interest rates by fiat; increasing the monetary base; and decreasing reserve requirements.
Selling securities has the effect of reducing the monetary base (because it accepts money in return for purchase of securities), taking that money out of circulation.
