🌋 Pahoehoe vs A'a Lava: Viscosity & Strain-Rate Texture Lab (2D)

This 2D companion isolates the rheology that decides lava surface texture: an Arrhenius viscosity–temperature law combined with an Einstein–Roscoe crystal-content correction sets the melt's effective viscosity, a slope-driven kinematic shear rate sets how fast the crust is being strained, and their ratio — a Deborah number comparing strain rate to the crust's viscous relaxation rate — decides whether the cooling skin folds smoothly into ropy pahoehoe or fractures into rubbly a'a clinker, live, as you move the temperature, slope and crystal-content sliders.