Basaltic lava flow surface morphology: Genesis, evolution and impact on flow dynamics

The emplacement of basaltic lava flows is impacted by a number of interdependent parameters. For the purposes of predictive modeling and hazard assessment, it is necessary to obtain ranges for these parameters and to understand how they are dependent on each other. This dissertation includes several studies to infer lava flow emplacement parameters and their relationships to one another from the surface morphology preserved on solidified flows.;Surface morphology maps of a number of Kilauean lava flows reveal a characteristic lava flow facies evolution that results in a sigmoidal surface morphology evolution with distance. I find that differences in the length scale of the transition relate to the eruption temperature and effusion rate of the lava for the transition onset, and interaction with local topography and resulting enhanced thermal efficiency for the transition length.;In addition to examining the flow-scale surface morphology transition, I use a corn syrup-rice suspension to investigate the transition at the local-scale. I find several distinct styles of deformation including clumping, shear zones, and detachment whose onsets follow an inverse relationship between particle concentration and shear rate. Each style of deformation shows progressively enhanced shear localization and any or all of these processes may be responsible for the transition from pahoehoe- to `a`a-type deformation.;Lava flow surfaces can also impact flow dynamics, with progressively thickening crusts providing increased resistance to flow as illustrated qualitatively by experiments using polyethylene glycol (PEG) 600 wax. I conduct a series of experiments to characterize the mechanical properties of solidified PEG and find that its strength is 104 times stronger than predicted from flow simulations, suggesting that a sub-surface visco-elastic layer, rather than the solidified crust, provides the primary resistance to PEG, and by analog, lava flows.;Finally, I develop a computational code to identify alignments of volcanic vents, which act as an indicator of the tectonic stress field at the time of emplacement. The code includes several filtering criteria to limit the detection of spurious alignments. I apply the code to a data set of Pacific Northwest vents and find a slight progressive clockwise rotation of the Cascade trend and westward impingement of the Brothers trend over the last 1 Ma.;This dissertation includes published, co-authored materials.