FLOWGO: a kinematic thermo-rheological model for lava flowing in a channel

We present a kinematic, self-adaptive, numerical model to describe the down -now thermal and rheological evolution of channel-contained lava. As our co ntrol volume of lava advances down a channel it cools and crystallizes, an increasingly thick and extensive surface crust grows, and its heat budget a nd rheology evolve. By estimating down-flow heat and velocity loss, our mod el calculates the point at which the control volume becomes stationary, giv ing the maximum distance lava flowing in the channel can extend. Modeled ef fusion rates, velocities, widths, surface crust parameters, heat budget, co oling, temperature, crystallinity, viscosity, and yield strength all compar e well with field data collected during eruptions at Mauna Loa, Kilauea, an d Etna. Modeled lengths of 25-27, 2.5-5.7, and 0.59-0.83 km compare with me asured lengths of 25-27, 4, and 0.75 km for the three flows, respectively. Over proximal flow portions we calculate cooling, crystallization, viscosit y, and yield strength of 1-10 degreesC km(-1): 0.001-0.01 volume fraction k m(-1), 10(3)-10(4) Pa s, and 10(-3)-10(2) Pa, respectively. At the flow fro nt, cooling, crystallization, viscosity, and yield strength increase to >10 0 degreesC km(-1), 0.1 volume fraction km(-1), 10(6)-10(7) Pa s, and 10(3)- 10(4) Pa, respectively, all of which combine to cause the lava to stop Bowi ng. Our model presents a means of (a) analyzing lava flow thermo-rheologica l relationships; (b) identifying important factors in determining how far a channel-fed flow can extend; (c) assessing lava flow hazard; and (d) recon structing flow regimes at prehistoric, unobserved, or remote flows.