Faster plates yield more, smaller volcanoes in a longer chain.
Volcanic eruptions can occur years to tens of thousands of years apart.
So next eruption will often form new caldera. Lava must flow downhill, and can do so rapidly and for great distances if the cooling time is long. Again liquid always runs downhill. Sediment carried from one spot must be deposited someplace else, usually in a characteristic delta pattern. It takes a lot of liquid to move a small amount of solid material.