Rhyolite lava emplacement dynamics inferred from surface morphology captured with drones.

The fluid dynamic properties of lava control the formation of morphologic features during emplacement. Therefore, fluid dynamic properties of the lava during emplacement can be inferred by measuring morphologic features on rhyolite lava flows. I analyzed surface features of rhyolite lava flows using high-resolution digital elevation models (DEMs) and orthomosaics made from unmanned aerial vehicle (UAV) structure-from-motion photogrammetry. I compare our newly acquired datasets to DEMs of rhyolitic lava flows from across the western USA, including Rock Mesa, Newberry, Obsidian Flow, Interlake Flow, and Banco Bonito. I measured ridge spacing, vergence angle of the axial plane of fold, block size distributions, and overall flow morphology. Pressure ridges range from 10 to 87 m, and block sizes from 0.5 to 0.7 m. These estimate interior viscosities from 109.7 to 1012.5 Pa s. Ranges of timescale can be estimated to be 30 – 548 days with eruptive fluxes from 8 – 135 m3 s-1