Progress toward a porous flow model for the emplacement of pahoehoe flow fields

Introduction: The emplacement of compound pāhoehoe flow fields involves the extrusion of thousands of individual meter-scale lobes, each governed by local heterogeneities in the topography and previously emplaced lava. Despite this, the overall advance of the flow field, and the formation of preferred lava pathways within it, appear to be governed by larger-scale properties of the environment and eruption (Fig. 1). There has been some success in modeling this behavior through the mathematics of a biased random walk [1]. Here we examine a moderately different technique to predict large-scale behavior when the small-scale processes are chaotic, building upon methods used to model flow through porous media. Figure 1. Stereotypical geometry of simple and compound (i.e., pāhoehoe) lava flow fields [2]. Vents are shown in red, actively flowing lavas in pink, and stagnant or frozen lava in grey. Planview on top, cross sections underneath. The more straightforward nature of simple flows has made them more amenable to modeling.