Consider running a moving average calc of volume along your date axis.
Give your user a parameter that lets them specify what a "substantial" change is. (10%? 2%?) Also give them a parameter that lets them decide how far to look back to determine the period over which you define "change". (1 day? 7 days?)
So maybe you don't care about a 2% change over 365 days. But maybe you want to see when there is a 5% or more change within 10 days of a price change.
You can do a LOOKUP([moving average of volume], -([days to examine parameter]) and that will look at volume x-many days ago. Get the absolute difference between today and the LOOKUP value. Also do the same LOOKUP to see if price has changed since x-many days ago.
And then it's just a matter of arithmetic to mess with all those numbers.