HR: 0800h
AN: V21A-0379    [Abstracts]
TI: The Importance of Surface Features in Long-lived Lava Flows: Preparing the way for Compound Lava Flow Models.
AU: Pinkerton, H
EM: h.pinkerton@lancaster.ac.uk
AF: Department of Environmental Sciences, Lancaster University, Lancaster, LA14YQ, United Kingdom
AU: * Applegarth, L J
EM: jane.applegarth@univ.oxon.net
AF: Department of Environmental Sciences, Lancaster University, Lancaster, LA14YQ, United Kingdom
AU: James, M R
EM: m.james@lancaster.ac.uk
AF: Department of Environmental Sciences, Lancaster University, Lancaster, LA14YQ, United Kingdom
AU: Calvari, S
EM: calvari@ct.ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania, Piazza Roma 2, Catania, 95123, Italy
AB: There have been significant advances in the development of lava flow models during the past decade, and their ability to replicate the emplacement of single flow units is very impressive. However, long-lived eruptions often produce compound `a`a flow fields containing many complex features of enigmatic origin, whose significance needs to be understood before such flows can be successfully modelled. The 2001 flank eruption of Mount Etna (17th July – 9th August) provided an excellent opportunity to observe the emplacement of a compound lava flow field. Twenty three days of activity at a single vent on the southern flank produced the lower flow field, which reached its maximum length in 7 days and thereafter grew by the superimposition and juxtaposition of younger flow units, and break-outs from earlier channels. Several sets of data were collected during the eruption, and we have combined the examination of these with detailed analysis of post-emplacement aerial photographs and our own recent field observations, in order to unravel the temporal evolution of the flow field. We are able to distinguish between features reflecting emplacement processes in individual units; those resulting from channel drainage, inflation, squeezing of lava from an older unit when overridden by a younger unit; and post emplacement changes including the emergence of lava in a range of rheological states through flow surfaces, flow margins and levee-channel boundaries. Although no lava tubes were encountered during our field survey, there is clear evidence of preferential thermal pathways within stationary flow units. Had the eruption continued, there is a high probability that a tube system would have developed, as was the case during the 1983, 1991-3 and 2004 eruptions. This would have allowed the flow to extend significantly further, resulting in greater damage to property on this heavily populated side of the volcano. The widespread occurrence of the structures described indicates that the underlying processes responsible for their development are common and repeatable, and therefore amenable to inclusion in future flow models.
DE: 8414 Eruption mechanisms and flow emplacement
DE: 8425 Effusive volcanism
DE: 8429 Lava rheology and morphology
DE: 8486 Field relationships (1090, 3690)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting