LAVA TUBE FLOW: CONSTRAINTS ON MAXIMUM SUSTAINED ERUPTION RATES FOR MAJOR MARTIAN VOLCANIC EDIFICES

Mars has more than half a dozen major volcanic constructs, including Olympus Mons, Alba Patera, Elysium Mons, Syrtis Major, Arsia Mons, Pavonis Mons, Ascreaus Mons, and Syria Planum. These systems are well known for their massive sizes and aerial extents. It has long been known that martian volcanic constructs can produce very large flow features, but not whether large flow sizes are directly correlated with volcanic construct size. Is the magmatic plumbing of large systems expressed in larger flows or is large system size a result of modest flows over longer eruptive periods? Recent Mars Global Surveyor and Mars Odyssey missions have returned higher resolution and higher accuracy topographic and image data that allow us to more accurately constrain lava flow rate models. Since lava tube flows tend to indicate steadier eruption conditions than lava channels, lava tube flow rates should reflect the most sustainable steady eruption rates for each system. We examine the largest tube flows for each major volcanic system to constrain the maximum steady and sustained eruption rate capability. We then test whether these maximum eruption rates correlate with estimated total volcanic construct volumes. We measure tube flow characteristics (local slopes, flow volumes, widths, heights, as well as channel or tube depths, widths, and cross section areas) for the largest lava tube flows observed for each major system. We use these as constraints in Newtonian sheet, channel, and tube flow models to calculate volumetric flow rates, assuming similar density and viscosity properties for all systems. Preliminary results indicate a possible inverse correlation between volcanic construct volumes and maximum modeled sustainable eruption rate. This suggests that the volumetrically largest constructs are more likely to be the result of relatively moderate eruptions over long time scales.