HR: 1340h
AN: V53B-1567    [Abstracts]
TI: Quantitative Flow Morphology, Recent Volcanic Evolution and Future Activity of the Kameni Islands, Santorini, Greece
AU: Elliott, J R
EM: jrelliott@gmail.com
AF: University of Oxford, Department of Earth Sciences Parks Road, Oxford, OX1 3PR United Kingdom
AU: * Pyle, D M
EM: dmp11@cam.ac.uk
AF: University of Cambridge, Department of Earth Sciences Downing Street, Cambridge, CB2 3EQ United Kingdom
AB: The fundamental importance of careful field investigation, and the long term value of detailed published volcanic eruption reports, means that much can be learned about eruption processes even many decades after an eruption has ceased. We illustrate this with reference to the young dacite lava flows of the Kameni islands, Santorini. We have created a new, high resolution digital elevation model (DEM) for the intra-caldera Kameni islands, Santorini, based on new data from a recent airborne laser-ranging (LiDAR) and aerial photography mission. This DEM reveals a wealth of surface morphological information on the dacite lava flows that comprise the Kameni islands. When combined with a re-analysis of contemporary eruption accounts, these data yield important insights into the physical properties and flow behaviour of dacite magma during slow effusive eruptions. Kameni island lava flows exhibit the classic surface morphologies associated with viscous aa: levees, and compression folds. Levee heights and flow widths are consistent with a Bingham rheology, and lava yield strengths of (3 to 7)× 10⁴ Pa. Analysis of the shapes of flow edges confirms that the blocky aa dacite lava flows show a scale-invariant morphology with a typical fractal dimension that is indistinguishable from Hawaiian aa. Dome-growth rates during eruptions of the Kameni islands in 1866 and 1939 are consistent with a model of slow inflation of a dome with a strong crust. Lava domes on the Kameni islands have a crustal yield strength (4×10⁷ Pa) that is lower by a factor of 2 to 4 than the domes at Pinatubo and Mount St Helens. The dome height model, combined with the apparent time-predictable nature of volcanic eruptions of the Kameni islands, allows us to predict that the next eruption of the Kameni islands will last for > 2.6 years (in 2005) and will involve formation of a dome ca. 115 to 123 m high.
DE: 8414 Eruption mechanisms and flow emplacement
DE: 8425 Effusive volcanism
DE: 8429 Lava rheology and morphology
DE: 8485 Remote sensing of volcanoes
DE: 8486 Field relationships (1090, 3690)
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005