HR: 16:30h
AN: V24A-03    [Abstracts]
TI: Techniques for Optimising Data From Thermal Imaging Cameras on Active Volcanoes and Implications for Modelling Lava Flows
AU: * Pinkerton, H
EM: h.pinkerton@lancaster.ac.uk
AF: Lancaster University, Bailrigg, Lancaster, Lan LA1 4YQ United Kingdom
AU: Ball, M
EM: m.ball@lancaster.ac.uk
AF: Lancaster University, Bailrigg, Lancaster, Lan LA1 4YQ United Kingdom
AU: James, M
EM: m.james@lancaster.ac.uk
AF: Lancaster University, Bailrigg, Lancaster, Lan LA1 4YQ United Kingdom
AU: Cashman, K
EM: cashman@uoregon.edu
AF: University of Oregon, 1272 University of Oregon, Eugene, OR 1272 United States
AB: Following a systematic series of laboratory experiments using different thermal imaging cameras, it is now possible to determine surface temperatures of volcanic rocks in the laboratory over a range of temperatures and viewing angles with a precision of 0.8%. Extracting useful temperature data in the field is more challenging. Current methods of dealing with pixel integrated temperatures make assumptions that are not always realistic. Another major source of error is gas attenuation. Field experiments on active lava flows on Etna, Sicily during the past 5 years have revealed differences in the apparent temperature of the surface of lava viewed through skylights in excess of 80 C, even at viewing distances less than 5 metres. The effect of viewing angle is more complex in the field than in the laboratory, and can result in similar errors in measurements of apparent temperatures. However, each of these errors can be significantly reduced if appropriate precautions are taken. A strategy for optimum use of thermal imaging cameras will be presented, together with a comparison of measured and modelled cooling trends on different lava flows. We will also argue that critical transitions in surface textures on Etna are not controlled by increases in crystallinity, but instead are dependent on a combination of surface temperature and strain rates. This is in marked contrast with flows on Hawaii where crystal content plays a dominant role in these transitions. We will show that accurate prediction of these transitions is essential for realistic modelling of lava flows.
DE: 8414 Eruption mechanisms and flow emplacement
DE: 8425 Effusive volcanism
DE: 8429 Lava rheology and morphology
DE: 8485 Remote sensing of volcanoes
DE: 8494 Instruments and techniques
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005