A Global Survey of Lithospheric Flexure at Steep-Sided Domical Volcanoes
on Venus Reveals Intermediate Elastic Thicknesses
Topographic flexure in response to vertical loads reveals key
lithospheric properties, including elastic thickness and the heat flow
from the interior. Flexural stresses may also control volcano
morphology. One previous study predicted that steep-sided domes on Venus
usually form where the elastic thickness is ~15-40 km.
We surveyed flexural signatures around steep-sided domes and confirmed
this hypothesis. We determined elastic thickness from topographic
profiles with a curve-fitting algorithm and a plate bending model in
Cartesian and axisymmetric geometry. We used a yield stress envelope to
convert elastic thickness and plate curvature into mechanical thickness
and surface heat flow. The average elastic thickness for domes not near
coronae is ~30 km, corresponding to a heat flow of
~60 mW/m2. Coronae on Venus are
typically associated with elastic thicknesses of <10-15 km.
Domes near coronae yielded elastic thicknesses in this range, and higher
heat flows than domes not near coronae.