How lava flows: New insights from applications of lidar technologies to lava flow studies

Mafi c lava fl ows are common; for this reason, they have long been a focus of volcanological studies.However, fi eld studies of both older and active fl ows have been hampered by diffi culties in fi eld access; active fl ows are hot, whereas older fl ows have rough and jagged surfaces that are diffi cult to traverse.As a result, morphometric studies of lava fl ows have generally lagged behind theoretical studies of fl ow behavior.The advent of laser scanning (LS) (i.e., lidar, light detection and ranging) technologies, both airborne mapping (ALSM) and terrestrial (TLS), is promoting detailed studies of lava fl ows by generating data suitable for production of high-resolution digital elevation models (DEMs).These data are revolutionizing both the visual and quantitative analysis of lava fl ows.First and foremost, this technology allows accurate mapping of fl ow boundaries, particularly in vegetated areas where bare earth imaging dramatically improves mapping capabilities.Detailed imaging of fl ow surfaces permits mapping and measurement of fl ow components, such as channels, surface folds, cracks, blocks, and surface roughness.Differencing of preeruptive and posteruptive DEMs allows analysis of fl ow thickness variations, which can be related to the dynamics of lava emplacement.Multitemporal imaging of active fl ows provides information not only on the rates and locations of individual fl ow lobes, but also measurement of pulsed lava transport.Together these new measurement capabilities can be used to test proposed models of channel formation, lava tube formation, rates of fl ow advance, and fl ow conditions within lava channels; they also provide new ways to assess the hazard and risk posed by lava fl ow inundation.Early published studies illustrate the potential of applying lidar to volcanic terrain; it is clear, however, that the availability of high-resolution digital topography is poised to revolutionize the study of mafi c lava fl ows.