Generally, after a big move, the trading volume is falling. Then there is a period of accumulation / distribution - in this phase the trading volume is much lower than during a big move.
However, looking at the price / volume action, presented by US indice,s I see something totally different - let me take S&P 500 as an example:
Since the middle of January we saw very high volatility but basically the index was trading between 1,870 - 1,950 points. The strange thing is that the accompanying trading volume was very high - most frequently around 3.1 - 4.5 billion shares were changing hands every day.
To show this situation better - the chart below presents the 10-day volume average:
Here we may spot that since January 7, 2016 the average volume went quickly up from around 1.9 billion shares to 3.3 billion shares a day.
Well, when prices go nowhere and volume is rising rapidly the market wants to say something important. In my opinion, the message is: SOMETHING BIG IS IN THE MAKING...