Thermal and Rheological Controls on the Emplacement of Basaltic Lava Flows

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Thermal and Rheological Controls on the Emplacement of Basaltic Lava FlowsEAR-0207919PIs: Cashman & KauahikauaThis is a renewal proposal that follows directly in theme and approach to the previous award. Recent studies of active pahoehoe and `a`a flows in Hawai`i, including those by the PIs, have shown that the explicit link between flow morphology and emplacement involves the relative rates of cooling, crystallization, and flow advance. Critical are conditions of lava transport from the vent to the flow front. Field observations of flow surface morphologies have led to rheological studies on yield strength development in crystal-liquid suspensions. Novel experiments using PEG wax suggest that solidification in uniform channelized flows may be described by a single dimensionless parameter and channel aspect ratio. Non-uniformities such as channel divergences, constrictions, and sinuosity also may stabilize or disrupt surface crust. Results from the previous award illustrate the success of these approaches. The current award will use high resolution satellite remote sensing to map basaltic flows, complete additional analog experiments to better define important material parameters and flow controls, and compare model predictions with detailed field observations of flows. This renewal award continues support for the collaboration between Cashman (Univ. of Oregon), Kauahikaua (U.S.G.S., Hawaiian Volcano Observatory), and Griffiths & Kerr (Australian National University). The research team brings together expertise on the field mapping and interpretation of Hawaiian lava flows and expertise on fluid mechanical analysis of solidifying flows.