HR: 08:35h
AN: V11B-03 [PDF]
TI: Modeling the Growth of Hawaiian Volcanoes
AU: * Baker, M B
EM: mikeb@gps.caltech.edu
AF: Div. Geol. Planet. Sci., Caltech, Pasadena, CA 91125 United States
AU: Stolper, D A
EM: d_stolper@yahoo.com
AF: Div. Geol. Planet. Sci., Caltech, Pasadena, CA 91125 United States
AU: Stolper, E M
EM: ems@gps.caltech.edu
AF: Div. Geol. Planet. Sci., Caltech, Pasadena, CA 91125 United States
AU: Fialko, Y
EM: fialko@radar.ucsd.edu
AF: Scripps Inst. Oceanography, UCSD, La Jolla, CA 92093 United States
AB:
We have developed a numerical model that simulates the growth of either single or multiple volcanoes upon the sea floor. The
goal is to visualize the coupled growth, subsidence, and interactions of Hawaiian volcanoes as they move over their
underlying mantle sources. Volcano growth is modeled in 2000-year time steps. In each time step, magma is distributed over
the surface of each volcano according to simple rules (e.g., magma always flows downhill via a steepest descent path), after
which the volcanic edifice subsides assuming it rests upon an elastic plate of fixed thickness. The flux of magma for each
volcano in each time step is based on the plume flux model of DePaolo \& Stolper [1996], in which each volcano captures all
the melt flux within the intersection between a circular capture area centered beneath the volcano's summit and a cylindrical
mantle plume (zoned with respect to melt flux from the center to the edge of the plume). Thus, the magma flux to each
volcano varies with time as the circular capture area passes over the mantle plume. Using this model, we explored volcano
growth rates (and related parameters such as basal and island radii and ratio of submarine to subaerial lava) as functions of
a variety of factors such as the offset of the volcano relative to the center of the plume, the relative positions of
multiple volcanoes, and the existence and orientations of rift zones. We have also investigated the three-dimensional shape
of the submarine-to-subaerial transition surface; subsidence rates as a function of plate thickness, distance from a
volcano's summit, and time; and the geometries of zones in which lavas from two or more volcanoes interfinger. For the case
of a single volcano growing on an elastic plate, growth rates and ratios of submarine to subaerial lavas are similar to those
calculated by DePaolo \& Stolper [1996] from simple geometrical constructions. A seven-volcano model with volcanic centers
located at the positions of actual Hawaiian volcanoes reproduces the overall morphologies of volcanoes on the island of
Hawaii (elevations, slopes, shorelines) as well as the surface distributions of lava flows from the different volcanoes, and
makes model-dependent predictions of the volumes and subsurface structure of the individual volcanoes.
DePaolo \& Stolper [1996] JGR 101, 11643-11654.
DE: 1208 Crustal movements--intraplate (8110)
DE: 1236 Rheology of the lithosphere and mantle (8160)
DE: 8499 General or miscellaneous
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting