Time evolution of select key mantle variables for an evolution with Type IV behavior. Panel (A) plots the upper mantle and solidus temperatures over time; panel (B) shows the depth to the bottom of the stagnant lid layer and the upper mantle thermal boundary layer; panel (C) shows the upper mantle viscosity; panel (D) shows the eruption rate; panel (E) shows the different heat sources and sinks (cooling mechanisms) for the mantle, and panel (F) shows the evolution of the water reservoirs in the simulation. Note that the characteristic Type IV oscillations occur most strongly in any parameter related to the viscosity (the eruption rate, stagnant lid and thermal boundary layer thicknesses, and convective cooling). Parameter choices for this evolution can be found in Table 11.