A non-isothermal viscoplastic thin-layer theory is developed to explore the effects of
surface cooling, yield stress, and shear thinning on the evolution of non-isothermal
domes of lava and laboratory fluids. The fluid is modelled using the Herschel–Bulkley
constitutive relations, but modified to have temperature-dependent viscosity
and yield stress. The thin-layer equations are solved numerically to furnish models
of expanding, axisymmetrical domes. Linear stability theory reveals the possibility of
non-axisymmetrical, fingering-like instability in these domes. Finally, the relevance to
lava and experiments is discussed.
