This change in the pattern of eruptive activity from large ignimbrites to smaller domes reflects a change in the nature of the magma supply, from large volume flow that heavily interacted with the crust and gave rise to the ignimbrites to smaller volume flows in a colder and thus brittler crust and did not accumulate or interact with it in a significant way.
This alteration in eruptive patterns from large ignimbrites to smaller domes indicates a shift in magma supply characteristics, transitioning from high-volume flows that extensively interacted with the crust and produced ignimbrites to lower-volume flows in a colder, more brittle crust that did not significantly accumulate or interact with it.