We present a self-consistent crustal accretion model of Iceland that i
ncludes heat and mass transfer between an upwelling, melting mantle an
d an accreting, cooling crust. This models predicts sub-solidus crusta
l temperatures that are consistent with seismic estimates of the maxim
um depth of earthquake hypocenters and mid-crustal shear wave quality
factors, and with geothermal estimates of surface heatflow.