Resolution and error constraints of topographic measurements for accurate lava flow forecasting

The main parameters required to forecast lava flows are the eruption effusion rate, the lava viscosity, and the pre-eruption topography. We focus on how the spatiotemporal resolution and vertical errors of topographic measurements affect lava flow forecasts. We develop a basic fluid mechanical flow model that, combined with theory, allows us to study the propagation of lava flows on simple noisy topography. We find that topographic noise acts to retard and widen the flow and show that relative noise greater than approximately 10% of the flow thickness significantly reduces the simulated advance rates and compromises the retrieval of the other eruption parameters. We also analyze how vertical topographic error, spatial sampling, and the time sampling frequency affect the effusion rate uncertainty. This work provides a basis for understanding how repeat topography data sampling and precision can affect forecasting lava flow spatiotemporal inundation and inform observation needs from future topography missions.