As a forex trader, if you check several different currency pairs to find the trade setups, you should be aware of the currency pairs correlation, because of two main reasons:
1- You avoid taking the same position with several correlated currency pairs at the same time and so you do not increase your risk. Additionally, you avoid taking opposite positions with the currency pairs that move against each other, at the same time.
2- If you know the currency pairs correlations, it may help you predict the direction and movement of a currency pair, through the signals that you see on the other correlated currency pairs.
If you would like more information describing the affects - reply with a short note and I will paste a URL
in order for me to start looking for potential trend reversals. Your chart is fascinating but I agree with another trader that it is cancellation rather than correlation. let's study things some more.