REPEAT TOPOGRAPHIC SURVEYS FOR CHARACTERIZING ERUPTION DYNAMICS AND ASSESSING HAZARDS DURING THE 2018 KILAUEA LOWER EAST RIFT ZONE ERUPTION (Invited Presentation)

The 2018 eruption from Kīlauea’s Lower East Rift Zone in Hawai‘i produced ~1.2 km³ of lava over more than three months and destroyed infrastructure and homes across the lower Puna District. This effusive eruption caused rapid and dramatic topographic change, with significant implications for tracking the emplacement and growth of the lava flows, as well as assessing the ever-changing areas at risk from lava inundation as the eruption progressed. We integrated repeated assessment of topographic change with lava flow modeling to provide timely data and analysis to emergency managers while capturing the three-dimensional evolution of the lava flow field in detail. High resolution (0.1–3 m) digital elevation models (DEMs) were produced as frequently as possible (minimum of 45 minutes) throughout the eruption to update topography for new lava flow forecasts and document the changing volume and morphology of the lava flow field. These data were primarily derived through repeated surveys by small unoccupied aircraft systems (sUAS) collecting photographs for structure-from-motion photogrammetry processing, in addition to two syn-eruptive lidar surveys and seven flights of NASA’s GLISTIN-A airborne InSAR instrument that provided broader spatial coverage. To produce lava flow forecasts, flows were modeled from active vents and overflow locations over these up-to-date DEMs using the DOWNFLOW model and similar codes based on steepest-descent paths and approximating flow thickness and ponding. Fast topographic data processing and rapid modeling allowed for flow forecasts to be issued promptly and improved accuracy during eruption response. Topographic change was also analyzed to monitor the evolution in lava volume and morphology through time. Initial results, in conjunction with submarine bathymetry data, show a total volume of 1.2 km³ and an increase in eruption rate from ~7 m³/s in early May up to >150 m³/s by July. Analysis of flow morphology shows the establishment and evolution of the channel system, levees, and surface textures over the course of the eruption and with distance from vent, providing an unprecedented dataset for understanding lava flow dynamics. Our results demonstrate the value of repeat high resolution topographic surveys for hazard response and volcanology.