The buried caldera of Misti volcano, Peru, revealed by combining a self-potential survey with elliptic Fourier function analysis of topography - Laboratoire Magmas et Volcans Accéder directement au contenu
Article Dans Une Revue Journal of Volcanology and Geothermal Research Année : 2005

The buried caldera of Misti volcano, Peru, revealed by combining a self-potential survey with elliptic Fourier function analysis of topography

Résumé

This survey proposes a new approach to identify buried caldera boundaries of a volcanic cone, combining (I) a systematic elliptic Fourier functions (EFF) analysis on the contour lines based on the external shape of the edifice with (2) self-potential (SP) measurements on volcano flanks. The methodology of this approach is to investigate the relationships between (1) vertical morphological changes inferred from EFF analysis and (2) lateral lithological transition inside the edifice inferred from SP/ elevation gradients. The application of these methods on Misti volcano in southern Peru displays a very good correlation. The three main boun daries evidenced by hierarchical cluster analysis on the contour lines coincide with the two main boundaries characterised by SP signal and with a secondary SP signature related with a summit caldera. In order to explain these results showing a very good correlation between morphologic and lithologic changes as function of elevation, caldera boundaries have been suggested. The latter would be located at an average elevation of (I) 4350-4400 m, (2) 4950-5000 m, and (3) 5500- 5550 m. For the lowest boundary in elevation, the coincidence with the lateral extension of the hydrothermal system inferred from SP measur ements suggests that caldera walls act as a barrier for lateral extension of hydrothermal systems. In the summit area, the highest boundary has been related with the summit caldera, inferred by a secondary SP minimum and geological evidence.
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Dates et versions

hal-01465828 , version 1 (13-02-2017)

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Anthony Tort, Anthony Finizola. The buried caldera of Misti volcano, Peru, revealed by combining a self-potential survey with elliptic Fourier function analysis of topography . Journal of Volcanology and Geothermal Research, 2005, 141, pp.283-297. ⟨10.1016/j.jvolgeores.2004.11.005⟩. ⟨hal-01465828⟩
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