Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/559
AuthorsLombardo, V.* 
Buongiorno, M. F.* 
Pieri, D.* 
Merucci, L.* 
TitleDifferences in Landsat TM derived lava flow thermal structures during summit and flank eruption at Mount Etna
Issue Date2004
Series/Report no./134(2004)
DOI10.1016/j.jvolgeores.2003.12.006
URIhttp://hdl.handle.net/2122/559
KeywordsLandsat TM;
thermal structures;
Mount Etna
Subject Classification04. Solid Earth::04.08. Volcanology::04.08.01. Gases 
AbstractAbstract The simultaneous solution of the Planck equation (the so-called ‘‘dual-band’’ technique) for two shortwave infrared Landsat Thematic Mapper (TM) bands allows an estimate of the fractional area of the hottest part of an active flow and the temperature of the cooler crust. Here, the dual-band method has been applied to a time series of Mount Etna eruptions. The frequency distribution of the fractional area of the hottest component reveals specific differences between summit and flank lava flows. The shape of the density function shows a trend consistent with a Gaussian distribution and suggests a relationship between the moments of the distribution and the emplacement environment. Because flow composition of Etnean lavas generally remains constant during the duration of their emplacement, it appears that the shape of any particular frequency distribution is probably related to fluid mechanical aspects of flow emplacement that affect flow velocity and flow heat loss and thus the rate of formation of the surface crust. These factors include the influence of topographical features such as changes in slope gradient, changes in volume effusion rate, and progressive downflow increases in bulk or effective viscosity. A form of the general theoretical solution for the ‘dual-band’ system, which illustrates the relationship between radiance in TM bands 5 and 7, corresponding to hot fractional area and crust temperature, is presented. Generally speaking, it appears that for a given flow at any point in time, larger fractional areas of exposed hot material are correlated with higher temperatures and that, while the overall shape of that distribution is common for the flows studied, its amplitude and slope reflect individual flow rheological regimes.
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