Collaborative Proposal: Evolution of Lava Channel Networks: Implications for Lava Flow Hazards and Mitigation

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Rivers of molten lava are iconic manifestations of volcanic activity in places like Hawaii. Although rarely fatal, lava flows commonly pose risks to property, risks that may be sufficient that government authorities decide to build barriers to divert those flows (for example, at Mt. Etna, Italy, in 1983, 1991 and 2001, and in Hawaii in 1960). However, barrier construction is more an art than a science, and the interaction between lava flows and topographic barriers has not been well researched. Barriers may also exist in the landscape over which lava travels, either in the form of pre-existing topography or in topography that is constructed as lava flows are emplaced and solidify. Lava flows that encounter barriers will either split around them to form separate (smaller and slower) lava flow lobes, or may be focused by large obstacles (such as cliffs) into large (and fast-moving) flows. These behaviors must be understood to model the advance of active flows, which is essential for assessing and mitigating volcanic hazards in regions of frequent lava flow activity (such as Hawaii, Italy and Iceland). This research will investigate the development and stability of complex lava flows using (1) analysis of channel networks preserved in recent Hawaiian lava flows, (2) laboratory experiments performed to determine the effect of obstacles on the downslope movement of viscous fluids (both analogue fluids and molten basalt) when they encounter topographic obstacles, and (3) models developed from the experiments and applied to active lava flows. Additionally, channel networks in recent Hawaiian lava flows will be identified on high resolution digital elevation models (DEMs) and aerial photos, analyzed for network patterns, and investigated in the field. Field studies will include documentation of lava-topography interaction structures via photogrammetry and construction of 3D models of specific channel features. New digital elevation models will be created for target areas using both TanDEM-X satellite-based radar imaging and by photogrammetry. This multi-pronged approach will be made possible by collaborations among scientists at the University of Oregon, University of Bristol, Lamont-Doherty Earth Observatory, and the USGS Hawaiian Volcano Observatory.