EXPERIMENTAL MODELING AND ANALYSIS OF THE EFFECT OF LAVA TUBE MORPHOLOGY ON MOLTEN, BASALTIC MATERIAL TRANSPORT

Basaltic, pahoehoe lava flows utilize many structural formations to ensure a minimum loss of heat and energy while maximizing dispersion of their molten material. Of these formations, pyroducts, commonly termed lava tubes, are ones often created to transport molten material great distances because of their insulating properties which minimizes heat loss within the flow. This study, conducted through the Keck Geology Consortium and the Syracuse University Lava Project¹, combined a field examination of the 1975-84 Krafla caldera lava flows of Northern Iceland with large-scale (>800lbs) laboratory modeling of man-made basaltic lava flows. Aimed at gaining a more detailed understanding of the formation and use of pyroducts in basaltic flows, this study focused specifically on ascertaining the relationship between conduit cross-sectional shape and effectiveness of molten material transportation. Previous studies of Hawaiian lava flows determined that a lava conduit’s cross-sectional shape will evolve through time from an initial flat, ellipse with width exceeding its height to that of a circle or vertical ellipse with height exceeding its width. In following these previous examinations of lava flows, this study aimed to determine the impact of these cross-sectional shapes on molten material transport effectiveness through controlled, large-scale lava flow modeled pours.

Three pour experiments were conducted using previous Lava Project¹ methods, each creating cross-sectional shapes that attempted to mirror the different stages of cross-section evolution in an aging pyroduct. Of the three created pyroducts, the average aspect ratios (height:width), ranged from 0.7:1.0 to 1.3:1.0. From these pours, collected data were analyzed and showed heat losses and significant viscosity differences, in addition to changes in other experimental metrics. While results indicate a possible correlation between tube morphology and molten material transport, further experimental trials are needed to obtain definite conclusions. Additional analysis is expected to show that tubes with a greater height than width will better insulate molten material and therefore increase transportation effectiveness.

¹ http://lavaproject.syr.edu