HR: 16:15h
AN: V14A-02    [Abstracts]
TI: Theoretical Model for Lava Flows in Confining Channels
AU: * Takagi, D
EM: dt268@cam.ac.uk
AF: Institute of Theoretical Geophysics, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA, United Kingdom
AU: Huppert, H E
EM: heh1@esc.cam.ac.uk
AF: Institute of Theoretical Geophysics, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA, United Kingdom
AB: Active lava flows down confining valleys are modelled as Newtonian viscous gravity currents. We determine the structure and the rate of propagation of the flow as functions of the form of the pre-existing topography, the effusion rate at the vent and the effective lava viscosity. When the confining boundary of the flow obeys a power- law with respect to the cross-slope coordinate, and the total volume of fluid obeys a different power-law with respect to time, the extent of the resulting flow can be determined analytically as a function of time for different channel shapes. The channel can be either horizontal or inclined, and its shape can vary gently along the downstream direction. The theoretical results are in excellent agreement with data from laboratory experiments, in which glycerine was released with either a constant volume or flux at one end of a long channel with either a semi-circular or V-shaped cross section. We will summarize the various different propagation rates that arise on different topographies. Applications to interpreting field data will be also presented.
DE: 8400 VOLCANOLOGY
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