A REMOTE SENSING APPROACH TO ASSESSING PAHOEHOE TO A’A TRANSITIONS IN MT. KILAUEA BASALT FLOWS

New data collected during the prolonged 2018 Mt. Kilauea LERZ (Lower East Rift Zone) eruption provide an excellent opportunity to assess models (such as the TTZ, Hon et al., 2002, Peterson and Tilling, 1980) that predict how different factors contribute to the pahoehoe-to-a’a transition in basaltic lava flows. Here, combining pre-, syn- and post-eruptive UAS LiDAR data with orthophotographs and thermal emission imagery, we seek to assess the role of slope, specifically the idea that variations in topography facilitate a’a formation by enhancing and altering key factors such as viscosity and shear stress/rate of shear strain (Peterson and Tilling, 1980). Using tools within ArcGIS’ Spatial Analyst and 3D Analyst extensions, geomorphological methods such as the Topographic Position Index, and statistical tests, we seek to identify and understand correlations between factors such as surface roughness, pre-flow slope, slope orientation, and the formation of a’a textures. Of particular interest is whether the spatial characteristics of a’a formation vary with time: in low-slope areas, is the formation of a’a linked predominantly to pre-flow slope, or does the location vary as the flow evolves? The data needed to acquire such insights are not commonly available, and thus we anticipate that results from our in-progress study can help improve our understanding of lava flow evolution and the assessment of hazards linked to lava flow emplacement.