“…As in Spencer, Katz, and Hewitt (2020) we assume that the emplacement rate of magma from the plumbing system to the continuum is proportional to the temperature difference between the plumbing system material and the local continuum where T e is an elastic limit temperature below which no emplacement occurs (Spencer, Katz, & Hewitt, 2020). The emplacement rate constant h is discussed at length in Spencer, Katz, and Hewitt (2020), but here we propose that it may have different values in the mantle h M and the crust h C (the crust is where T < T A ). The mechanisms by which magma propagates through a partially molten medium are likely to be very different to those in a solid, and so would be expected to have a different efficiency of magma transport.…”