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Image-based measurement of flux variation in distal regions of active lava flows.

James, Mike R. and Pinkerton, Harry and Robson, S. (2007) Image-based measurement of flux variation in distal regions of active lava flows. Geochemistry Geophysics Geosystems, 8 (3). ISSN 1525-2027

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    Abstract

    Understanding the processes involved with the advance of lava flows is critical for improving hazard assessments at many volcanoes. Here, we describe the application of computer vision and oblique photogrammetric techniques to visible and thermal images of active 'a'ā flows in order to investigate distal flow processes at Mount Etna, Sicily. Photogrammetric surveys were carried out to produce repeated topographic data sets for calculation of volumetric lava flux at the flow-fronts. Velocity profiles from a distal channel were obtained by rectification of a thermal image sequence and are used to investigate the rheological properties of the lava. Significant variations of the magma flux were observed, and pulses of increased flux arrived within the flow-front region on timescales of several hours. The pulses are believed to be the distal result of more frequent flux changes observed in the vent region. Hence they reflect the importance of flow processes which are believed to cause the coalescence of flux pulses along the channel system as well as short-period variations in effusion rate. In considering advance processes for the individual flow-fronts, it must be assumed that they were fed by a highly unsteady flux, which was volumetrically at least an order of magnitude lower than that observed near the vent.

    Item Type: Article
    Journal or Publication Title: Geochemistry Geophysics Geosystems
    Additional Information: Copyright (2007) American Geophysical Union.
    Uncontrolled Keywords: close-range photogrammetry ; thermal imaging ; lava flow ; Etna ; effusion rate ; rheology.
    Subjects: Q Science > QE Geology
    Departments: Faculty of Science and Technology > Lancaster Environment Centre
    ID Code: 941
    Deposited By: Dr Mike R. James
    Deposited On: 12 Feb 2008 08:55
    Refereed?: Yes
    Published?: Published
    Last Modified: 07 Apr 2014 14:12
    Identification Number:
    URI: http://eprints.lancs.ac.uk/id/eprint/941

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