Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/503
AuthorsTort, A.* 
Finizola, A.* 
TitleThe buried caldera of Misti volcano, Peru, revealed by combining a self-potential survey with elliptic Fourier function analysis of topography
Issue Date2005
Series/Report no.141(2005)
DOI10.1016/j.jvolgeores.2004.11.005
URIhttp://hdl.handle.net/2122/503
Keywordscaldera
elliptic Fourier functions
geomorphology
self-potential
Misti volcano
Peru
Subject Classification03. Hydrosphere::03.02. Hydrology::03.02.02. Hydrological processes: interaction, transport, dynamics 
03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes 
03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring 
03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases 
03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems 
04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes 
04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods 
04. Solid Earth::04.04. Geology::04.04.03. Geomorphology 
04. Solid Earth::04.04. Geology::04.04.09. Structural geology 
04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques 
04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks 
05. General::05.02. Data dissemination::05.02.04. Hydrogeological data 
05. General::05.05. Mathematical geophysics::05.05.99. General or miscellaneous 
05. General::05.08. Risk::05.08.99. General or miscellaneous 
04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk 
AbstractThis survey proposes a new approach to identify buried caldera boundaries of a volcanic cone, combining (1) 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 boundaries 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 (1) 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 measurements 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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