The 45 days window is perfect for it to achieve that much trading volume. With the holidays up-ahead many people do trade bitcoin for fun, for investments and part time stuff. This makes it more easier for bitcoin to go upwards and hold the ATH position.
From your graph itself we can make a match the current path is perfect one to reach 19-20k USD rates.
Not so fast if you look at the price chart for the volume right now you will see that the volume formed a double top and it only means that there is a chance of reversal going down for the volume, technical analysis formation also applies to other indicators such as volume so don't be surprised if we see lest trade activity going on in the few days. With the price going up and the volume going down the price rally will just get weaker and weaker.