Publications

Coppola, D; Laiolo, M; Franchi, A; Massimetti, F; Cigolini, C; Lara, LE (2017). Measuring effusion rates of obsidian lava flows by means of satellite thermal data. JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH, 347, 82-90.

Abstract
Space-based thermal data are increasingly used for monitoring effusive eruptions, especially for calculating lava discharge rates and forecasting hazards related to basaltic lava flows. The application of this methodology to silicic, more viscous lava bodies (such as obsidian lava flows) is much less frequent, with only few examples documented in the last decades. The 2011-2012 eruption of Cordon Caulle volcano (Chile) produced a voluminous obsidian lava flow (similar to 0.6 km(3)) and offers an exceptional opportunity to analyze the relationship between heat and volumetric flux for such type of viscous lava bodies. Based on a retrospective analysis of MODIS infrared data (MIROVA system), we found that the energy radiated by the active lava flow is robustly correlated with the erupted lava volume, measured independently. We found that after a transient time of about 15 days, the coefficient of proportionality between radiant and volumetric flux becomes almost steady, and stabilizes around a value of similar to 5 x 10(6) J M-3. This coefficient (i.e. radiant density) is much lower than those found for basalts (similar to 1 x 10(8) J m(-3)) and likely reflects the appropriate spreading and cooling properties of the highly-insulated, viscous flows. The effusion rates trend inferred from MODIS data correlates well with the tremor amplitude and with the plume elevation recorded throughout the eruption, thus suggesting a link between the effusive and the coeval explosive activity. Modelling of the eruptive trend indicates that the Cordon Caulle eruption occurred in two stages, either incompletely draining a single magma reservoir or more probably tapping multiple interconnected magmatic compartments. (C) 2017 Elsevier B.V. All rights reserved.

DOI:
10.1016/j.jvolgeores.2017.09.003

ISSN:
0377-0273